The supply of residential accommodation in a dwelling is exempt from GST.
Hotels, motels, other commercial dwellings, hospitals or residential establishments may include GST.
If your taxable activity is a hotel, motel, or other commercial dwelling, the GST on the accommodation (domestic goods or services) is calculated in 2 different ways:
- 4-week rule for commercial dwellings
- 4-week rule for residential establishments.
4-week rule for commercial dwellings
Charge GST on the full value of accommodation in hotels, motels and other commercial dwellings for the first 4 weeks' stay.
After 4 weeks, charge GST only on 60% of the value of the domestic goods or services. These are usually the right to occupy the premises and any of the following if they are included in that right:
- cleaning and maintenance
- electricity, gas, air-conditioning or heating
- telephone (not tolls), television, radio or similar chattels.
If a joint charge covers all supplies for bed and breakfast, the fully taxable supplies (breakfast) must be separately identified from the domestic goods or services (bed).
4-week rule for residential establishments, for example boarding hostels or rest homes
If there is an agreement that the stay is for more than 4 weeks, GST must be charged on 60% of the value of domestic goods or services from the start of the stay.
Rest homes and private hospitals
Standard rates were published in Tax Information Bulletin Vol 6, No 2 (August 1994) for the apportionment between domestic and non-domestic goods and services for rest homes and private hospitals.
The rates that will generally be acceptable for rest homes are:
- 45% domestic goods and services
- 55% non-domestic goods and services
The rates that will generally be acceptable for private hospitals are:
- 35% domestic goods and services
- 65% non-domestic goods and services
Rest homes and private hospitals may also use a factual basis for apportionment if they believe that the above rates are not consistent with the supplies they make, provided they have sufficient records to support their calculations.
A supplier who receives advance or progress payments must account for the GST on the payments. These are not financial services which would be exempt supplies but are inducements for a supply of goods.
For example, a payment from a marketing board to a grower is accounted for as follows:
The grower includes the payment in total sales in Box 5 of the GST return for the period they receive it.
If, for some reason, they have to pay back all or part of the advance they received from the marketing board it will be treated as a loan. The advance will be exempt from GST because it is a financial service.
The grower should ask us to reassess the return that included the advance payment.
The marketing board may claim a GST credit for the advance payment made, as long as the necessary tax invoice is held.
If the advance is later repaid, the repayment must be included in the total sales (Box 5). Any interest is exempt, as it is a financial service.
A GST-registered agent who is involved in the transaction must account for GST on any commission or fee.
Special rules apply if a New Zealand agent who is registered for GST acts on behalf of a non-resident principal who is outside New Zealand, and not registered for GST.
New Zealand agent buying supplies for a non-resident principal
The agent may, in certain circumstances, claim GST incurred when importing or exporting goods to or from New Zealand or arranging transportation.
Non-resident principal contracts services agent to sell and distribute their goods
In some cases a non-resident, non-registered principal may wish to sell goods in New Zealand but does not want to have a place of business here. They may contract the services of an agent to sell and distribute their goods.
If the New Zealand GST-registered agent and the principal agree, the agent will be responsible for returning GST on the sale of the goods rather than the non-resident. The agent will be able to claim GST incurred when importing the goods into New Zealand.
A non-resident art gallery decides to sell several pieces of art in New Zealand. The gallery arranges for a GST-registered agent in New Zealand to carry out the sale. The agent agrees to act as the supplier and importer of the artwork, rather than the art gallery. The agent may claim for any GST paid to import the goods and is responsible for charging GST on the sale of the artwork in New Zealand.
Who owns the goods
Ownership of goods under auction never passes to the auctioneer.
The auctioneers sell goods on behalf of other people, called principals. The auctioneer may not know whether the principals are registered for GST, or whether to charge GST on a particular lot.
Charging GST on the goods
The sale of goods on behalf of a non-registered principal is not taxable. The sale of a registered person's private assets is generally not taxable.
The auctioneer can charge and account for GST as though making the taxable supply, as long as both principal and auctioneer agree to this arrangement.
If the principal is registered, the GST-inclusive sale price, less commission, is passed on to the principal who must account for GST.
If the principal is not registered, the auctioneer will pass the GST-exclusive sale price, less commission, on to the principal.
An auctioneer who is registered for GST must account for the GST on fees or commissions.
Auctions may be conducted on either a GST-inclusive or a GST-exclusive basis. It should be stated at the beginning of the auction, so that the bidders know whether or not their bids include GST.
Supplying goods or services through a coin-operated device or machine
If you supply goods or services through any coin-operated device or machine, such as a video game, snack machine or parking meter, you must account for the total value of the coins removed from the machine.
Include the amount in the return that covers the date you removed the coins.
Making a supply through a token-operated device or machine
If you make a supply through a token-operated device or machine, you account for the tokens in the same way as other tokens, stamps or vouchers. The supplier should treat the token as a supply for GST purposes at the time the customer buys them.
Receiving business goods or services through a coin or token-operated machine
If you receive business goods or services through a coin or token-operated machine, you may claim a GST credit in the period you paid the money.
If a cheque is dishonoured, it is as though the payment did not occur, and you do do not account for it. Contact us to correct your return if you've already filed a GST return that includes a dishonoured cheque.
Note that this is only for people who are using the payments basis. For invoice and hybrid bases, this can only be reversed when it is written off as a bad debt.
If you're a door to door salesperson
The time of supply is the first day after the period the purchaser may cancel the sale in. Your buyers have either 7 days or 1 month to cancel the sale, depending on the cancellation period.
You account for the supply in the taxable period covering the day after the final date for cancellation.
For example, Kay, a door to door salesperson, sells an item on 31 May, the last day of the taxable period. The 8th day after the sale is 8 June. She includes the full price for the supply in the taxable period covering 8 June.
Purchasing from a door to door salesperson
You can claim a credit in the taxable period that covers the first day after the cancellation period, provided you hold a tax invoice.
This applies even if you get an invoice or make payment before that date.
The supplier (lessor) of goods under a finance lease can elect for the GST rate on payments made after 1 October 2010 to remain at the rate of 12.5% provided the:
- term of the finance lease began before 1 October 2010 and ends on or after 1 October 2010
- term of the finance lease is less than or equal to 5 years in length
- lessor advised the purchaser by no later than 31 October 2010 that the GST rate on payments after 1 October 2010 would remain at 12.5%.
If you make or receive payments for a finance lease after 1 October 2010 that have GST included at 12.5% you will need to account for these as an adjustment in the GST return for the period the payment is made or received in.
A finance lease eligible to have payments continue at the GST rate of 12.5% must have met the following criteria:
- periodic payments are made during the term of the agreement
- part of the amount payable under the agreement is towards credit (interest) under a credit contract
- if the agreement were to end early the final amount of GST calculated for the supply of goods would be calculated on the basis that the amount paid towards the credit (interest) had decreased with each periodic payment.
Calculating the GST component
The GST component of the payment can be calculated by dividing the amount of payment by 9.
If you are making the payment you include the adjustment as an "other" adjustment in Box 13 of your GST adjustments calculation sheet (IR 372).
If you are receiving the payment you include the adjustment as an "other" adjustment in Box 9 of your GST adjustments calculation sheet (IR 372).
If payment for goods or services is made in a foreign currency, convert it to New Zealand dollars using the exchange rate applying at the time the goods or services were supplied.
To claim a GST credit you must hold a tax invoice in New Zealand currency.
Sometimes a final price is not settled until after the goods are physically supplied.
If you are selling goods in this manner and you use the invoice or hybrid basis, include the GST in either:
- the earliest period an invoice is issued for any part of the supply
- when a payment is due
- when a payment is received.
If you purchase goods where the full price is not known, and you use the invoice basis either when:
- you claim a credit in the earliest taxable period that you receive a tax invoice
- you make a payment
- a payment is due.
Include the total amount invoiced, due or paid.
For purchases under the payments or hybrid basis, you claim a credit when you make a payment.
Gaming machines are machines that are constructed, designed or adapted for use in gambling.
Gaming machine duty and GST
If you operate gaming machines you should be registered for and paying gaming machine duty for each calendar month for all machines.
You must also pay GST on the value of the gaming machine revenue, which is:
- the increase in metered turnover
- less the increase in metered total wins during a return period.
The amount of any jackpots won during that return period is also deducted from total turnover if the jackpot figure is not included in the metered total wins.
Calculating gaming machine revenue
The gaming machine revenue for GST purposes is calculated from the information provided in the record keeping requirements for the Department of Internal Affairs.
If your monthly machine analysis reports or cashless gaming machine analysis reports are prepared to coincide with the last day of your taxable periods, the report(s) prepared during this period can be used to calculate the gaming machine revenue.
Paying problem gambling levy
A problem gambling levy is also payable on gaming machine profits. The problem gambling levy is calculated at 0.78% of all gaming machine profits plus GST. You may claim back the GST on problem gambling levy.
People on the invoice basis account for GST in full in the period any payment is made or invoice received in.
People on the payments basis account for GST when a payment is made in a period for the goods.
Grants and subsidies from the Crown or public authorities are considered to include GST if the recipient is registered for GST. Include the full grant or subsidy in Box 5 of your return.
An exception is grants intended for overseas use for international development. You will have to return GST only on the portion of the grant that is allocated for administration and capacity building in New Zealand.
If you receive a grant or subsidy from a government department, you do not normally need to issue a tax invoice. However, if you receive a grant or subsidy, such as a research grant from another registered person, you will probably be asked for a tax invoice.
If you pay a grant or subsidy in exchange for taxable supplies, you may request a tax invoice and claim a GST credit as usual.
George's wage subsidy
George employs 10 staff. He receives a wage subsidy of $200 per week for 8 weeks. The GST content would be $208.69.
$200 x 8 (weeks) = $1,600
$1,600 x 3/23 = $208.69
George includes $1,600 with sales in Box 5 of his return.
Hire purchase sales
You must account for all hire purchase sales in the taxable period covering the date you enter into the agreement, regardless of the accounting basis you use.
Buying goods on hire purchase
If you buy goods on hire purchase, you may claim a deduction in the taxable period covering the date you enter into the agreement, regardless of the accounting basis you use.
Rebecca sells a carpet on hire purchase to Emily on 7 June. The cash price is $550 including GST.
The agreement is for 36 monthly payments of $23, totalling $828. Rebecca accounts for the sale on the cash price of the goods ($550) in the period covering 7 June.
Emily also claims for her purchase on the cash price of the goods ($550) in the period covering 7 June. The difference of $278 is the finance charge, which is an exempt supply.
GST applies to certain supplies of services that are imported to New Zealand. For example:
- legal and accounting services
- products downloaded online.
If you are receiving imported services from an overseas supplier you may need to account for GST on the cost of the services, whether you are currently registered for GST or not. This is called "reverse charge". The reverse charge applies if the percentage intended or actual use of the imported services is less than 95% of the total use. The reverse charge requires you to add GST at 15% to the price of the services you have received.
There are special provisions if you are receiving the imported services from a non-resident member of the same GST group.
A person required to pay GST under the reverse charge is treated as the supplier of the services for registration purposes, payment of output tax and record keeping.
Accounting for and paying the GST
You include that amount in your GST return and pay it to us if all the following apply.
- Services are supplied by a non-resident supplier to a consumer who is a New Zealand resident.
- Services are acquired by a person who estimates at the time of acquisition that the percentage of intended use is less than 95%, or determines at the end of the adjustment period that the percentage of actual use is less than 95%.
- The supply of services would be a taxable supply if it were made in New Zealand by a registered person in the course of their taxable activity.
You may need to register for GST
If you have not previously been registered for GST, you will be required to do so if the value of imported services takes your turnover above the GST registration threshold of $60,000.
For more on GST on imported services see Tax Information Bulletin Vol 28, No 6, July 2016.
If you receive an insurance payment relating to your taxable activity, you must include the GST content as an adjustment in Box 9 of the return covering the time you received the payment.
What you don't need to account for
You do not need to account for any:
- insurance or compensation payment received for loss of earnings, such as accident compensation. However, the insurer will still charge GST on the premiums for this type of cover.
- payment received under a life insurance contract, as the insurer cannot charge GST on the premiums.
What insurers can claim for
Some types of insurance premiums are liable for GST, such as fire and general insurance. A registered insurer may claim deductions for payments to policy holders when they are made. A tax invoice is not needed.
The insurer needs a tax invoice to deduct any other payments for claims on policies, such as a payment to a panelbeater for repairs to an insured vehicle.
An insurer cannot claim for payments made under life insurance policies.
Graham's distilling equipment was damaged by fire on 20 January 2019. An insurance company issued a cheque on 18 March 2019 for $4,600 to cover the damage.
Graham includes $600 ($4,600 x 3 divided by 23) in Box 9 of the return for the taxable period covering 18 March 2019.
Time of supply
For GST purposes, the time of supply is the date the title of the asset passes to the purchaser. If the sale is cancelled and the seller keeps part of the money, the time of supply is the date of cancellation.
Accounting for the payments
Include the full cost of a layby sale in the taxable period the purchaser takes ownership of the goods. This is the time of the final payment.
Even if you use the payments basis, do not account for the lay-by payments as you receive each one, but wait until you receive the final payment.
For example, Marilyn buys a CD player on layby from Music Ltd in January. The full price is $560. Marilyn pays $160 as a deposit, and instalments of $200 in February and March. The CD player is delivered in April. Marilyn accounts for GST in the taxable period covering March, when the final payment was made and ownership changed.
When a lay-by sale is cancelled
If a layby sale is cancelled and the retailer keeps some of the payments already made (or receives payments later) this amount is accounted for in the taxable period the sale was cancelled in. GST is calculated on the full amount kept, or received later, and must be included in the return.
For example, Marilyn (see previous example) cancels the agreement in February, and receives a refund of $300. She has forfeited $60, which Music Ltd accounts for in the taxable period covering February.
If you purchase goods on layby, you may claim a deduction when you have fully paid for them, and you hold a tax invoice.
If you cancel a layby sale, you may claim 3/23 of any cancellation charge made by the supplier, in the period you cancel it, as long as you hold a tax invoice.
Local authorities are the only registered persons who charge rates.
Using the invoice or hybrids basis
A local authority that uses the invoice or hybrid basis, accounts for rates charged in full.
The time of supply for rates is the earliest of the:
- date of an instalment notice for a single payment
- due date for payment
- date when payment is received.
Using the payments basis
Using the payments basis, local authorities account for all payments of rates at the time they are received, regardless of whether they are paid in 1 instalment or several.
Registered persons claiming GST
Registered persons may claim GST for payments of rates for premises used in a taxable activity.
If you use the invoice basis and you pay rates in 1 lump sum, you may claim a GST credit when you make the payment or receive an invoice, whichever is earlier. If you pay rates in instalments, you may claim a credit when each instalment is due or paid, whichever comes first.
For the payments and hybrid basis, you claim a credit for rates when you make payment, provided you hold a tax invoice.
If you run raffles, lotteries, or other games of chance, you must account for the proceeds of the lottery (such as total sales of tickets or cards) less the total amount of cash prizes.
For example, if the total proceeds were $1,070 and total cash prizes were $800, the difference of $270 must be included in Box 5 of the return for the taxable period covering the date the raffle was drawn.
If 1 raffle has a number of draws, account for the GST in the return covering the date of the first draw.
You may claim GST on the purchase of non-cash prizes in the normal way, as long as you hold a tax invoice
When a supplier receives a deposit under a contract, the general time of supply will be triggered. This applies equally to conditional or unconditional contracts.
Where there is no binding contract or agreement, it must be shown that the payment is for the supply of goods or services, whether it occurs now or in the future.
Deposits paid to stakeholders
When a deposit is paid to a person as stakeholder, time of supply is not triggered as there was no receipt by the supplier.
A supplier may be a stakeholder. A stakeholder holds the deposit on behalf of both parties and owes a contractual obligation to both parties.
A stakeholder relationship requires agreement by all parties. A person cannot declare themselves a stakeholder unilaterally.
Sometimes the price of goods or services will change after an invoice has been prepared or a payment made.
Reduction of the agreed price
If you supply goods and services and reduce the price of the supply after issuing an invoice or receiving payment, you must include the amount of the reduction in the taxable period it was made in. This is usually the taxable period when the credit note was issued.
If you have already issued a tax invoice, you must always issue a credit note.
The buyer must include the reduction shown on the credit note in the return for the period covering the time of reduction. This is usually the period in which the credit note was received.
Increase of the agreed price
If you supply goods or services and increase the price of the supply after issuing an invoice or receiving payment, you must include the amount of the increase in the taxable period in which it was made. This is usually the taxable period in which you issued the debit note.
If you have already issued a tax invoice, you must issue a debit note for any increase in price.
The buyer must include the increase shown on the debit note in the return covering the time the increase was made. This is usually the taxable period in which the debit note was received.
Kevin's cleaning goods
Kevin sells cleaning goods to Maria for $1,000. Maria pays Kevin $900 as some goods were damaged. Kevin issues a credit note for $100. Both Maria and Kevin use the invoice basis.
Kevin includes $1,000 in Box 5 (sales) and $100 is claimed in Box 11 (purchases) in the return covering the time when the reduction was made.
If the invoice and credit note were issued in the same period, Kevin could have shown the net amount of $900 in Box 5 instead.
Maria claims $1,000 in Box 11 (purchases) and includes $100 in the total sales in Box 5, in the return covering the time when the reduction was made. If Maria received the invoice and credit note in the same period, she could claim the net $900 in Box 11.
Sonia sells goods worth $1,100 to Costa for $1,000 by mistake. Sonia then issues a debit note to Costa for $100. Both Sonia and Costa use the invoice basis.
Sonia includes $1,000 in Box 5 (sales). She also includes the extra $100 in Box 5, but in the return covering the period the increase was made.
Costa includes $1,000 in purchases in Box 11 and claims $100 in Box 11 in the return covering the time the increase was made.
If a registered person purchases a taxable activity that includes a dwelling, the dwelling must be treated as a separate (exempt) supply.
To be able to claim a GST credit in this case, the purchaser must show the extent that the dwelling is used in the taxable activity.
The purchaser may be able to claim some GST on the purchase and may need to make ongoing adjustments.
Progress payments, like periodic payments made under hire agreements, are treated as a series of separate supplies for each period of the agreement.
When is the time of supply?
The time of supply is the earlier of the time when a progress payment was made or when an invoice was issued.
The goods or services must be either supplied:
- progressively or periodically, and paid for in the same way
- directly in constructing, manufacturing or extending a building, or civil engineering work, with payments made periodically as the work progresses.
If you receive progress payments and you use the invoice or hybrid basis, either:
- account for the GST in the earliest taxable period that a payment is due or received
- issue an invoice for that payment only.
For the payments basis, account for GST when you receive any payments.
Claiming a GST credit
If you are making progress payments under the invoice basis, you may claim a GST credit either:
- in the earliest taxable period that a payment is due
- when you make a payment
- when you receive a tax invoice for that instalment.
For the payments and hybrid basis you claim a credit in the taxable period you make a payment in.
In hire purchase arrangements, goods are usually repossessed and resold if the buyer does not keep up the payments. If there is a forced sale, the original buyer (not the repossessor) is considered to supply the goods to the new purchaser.
Accounting for GST
If the goods sold are used in a taxable activity, GST must be accounted for when they are sold after repossession.
To account for the GST, the repossessor will need to file a special Goods and services tax return for goods sold in satisfaction of debt - IR373.
Gordon sells a $1,380 fridge on hire purchase to Bridget for her restaurant. Gordon accounts for GST of $180 ($1,380 x 3 divided by 23) in the return covering the period the agreement was made in.
Bridget does not keep up the payments.
Gordon repossesses the fridge and sells it again. He files a special return for goods sold in satisfaction of debt. The sale after repossession, and the GST to be accounted for on it, is considered to be made by Bridget.
If Gordon used an agent, Tim, to repossess the fridge, Bridget would still be considered to be making the sale and responsible for accounting for GST on it.
The agreement between Gordon (original vendor) and Tim (the agent) would determine who files the special return for the resale of the fridge.
Time of supply for road user charges is when any payment is made to the New Zealand Transport Agency or one of their agents.
You can only claim GST in the period when the payment is made.
The organisation is the registered person and not the individual members, if people are members of an unincorporated body, such as partnership, joint venture or trust.
If a member sells an interest in the organisation, there are no GST implications. It is a private transaction between 2 persons and not a taxable supply.
The same rules for GST and tax invoices apply to secondhand goods as for all other goods liable for GST.
What secondhand goods are
Secondhand goods are goods previously used and paid for by someone else. This includes land.
What secondhand goods are not
Secondhand goods are not:
- new goods
- primary produce (unless previously used)
- goods supplied under a lease or rental agreement
- goods consisting of any fine metal of any degree of purity.
Buying goods from a non-registered seller
If you are GST-registered you can claim a credit for GST purposes when you buy secondhand goods. If the seller is not registered for GST or the goods are private (exempt), there will be no tax invoice or GST charged.
Regardless of the accounting basis you use, you must make a payment before you can claim the credit for the purchase.
You must record:
- the name and address of the supplier
- the date of the purchase
- a description of the goods
- the quantity of the goods
- the price paid.
You'll also need to keep details of the transaction if you are going to make a claim for income tax purposes.
Exported secondhand goods
If you export goods after you've claimed a GST input credit for secondhand goods you've bought, you will not need to account for the GST input credit you have claimed when goods are sold if:
- the goods are entered for export
- the goods leave New Zealand within 28 days of the time of supply
- the recipient provides a declaration (for example, in the sale and purchase agreement or other sales document) at or before the time of supply that neither they nor an associated person will cause the goods to be re-imported to New Zealand in substantially the same condition in which they were exported.
If you make a supply of goods and services for more than $225,000 it must be accounted for using the invoice basis regardless of your accounting basis.
The general time of supply rule applies.
However, you can continue using your normal basis if the transaction is for a "short term agreement for the sale and purchase of property or services". This means that settlement must take place, or services must be performed, within 365 days of the date the agreement is entered into.
Special rules apply if you make certain supplies to people closely associated with you such as relatives, or closely connected associated companies or trusts.
Supply to registered associated persons
If you supply goods or services to an associated person who can claim a GST credit for the purchase, you account for GST on the amount received.
Supply to unregistered associated persons
If you supply goods or services to an associated person who cannot claim a deduction, you must determine the open (current) market value of the supply and account for the greater of the market value, or the amount you charged, in your return.
Taxable period the supply falls in
Include transactions with associated persons in the return for the taxable period you made the supply in. However, if you receive payment or issue an invoice before the last date for filing that return, the date of payment or invoice determines which taxable period the supply falls in, depending on your accounting basis.
Claiming GST on associated supplies
For the invoice basis, claim a deduction in the return for the taxable period the supply is made available in, removed or performed. However, if you make payment or receive a tax invoice before the last date for filing that return, the date of payment or invoice determines the taxable period.If you use the payments or hybrid basis, claim the GST as you make payments as usual.
Jones and Jones' piano
Jones and Jones, a GST-registered partnership sells a piano to Dawn, a sister of one of the partners. Dawn is registered for GST and can claim a GST credit on the purchase.
The open (current) market value of the piano is $2,000 but the sale is for $1,500. The partnership accounts for GST of $195.65 ($1,500 x 3 divided by 23).
Dawn's unregistered purchase
If Dawn (see previous example) was not registered for GST, the partnership would account for GST of $260.87.
This is the $2,000 market value multiplied by 3 then divided by 23.
A partnership has a 2-month taxable period. The return for the period ended 30 April is due on the last working day of May.
The partnership supplies goods with an open (current) market value of $115 to a non-registered brother of one of the partners on 24 April and receives payment of $100 on 16 June. The partnership will account for $15 GST (on the market value of $115) in the return for the taxable period ended 30 April, as this is the period in which the supply was made.
If the partnership had issued an invoice or received payment during May (before the April return was due to be filed), the $15 GST would be included in the return for the taxable period ended 30 June. This is because the invoice or payment would fall in the June period.
A registered person may invite tenders for a future supply of goods or services. The advertisement should state whether the tenders should include GST, so both parties know whether to allow for GST in the tender amount.
Occasionally the person making a tender will have to pay a deposit. There is no GST on the deposit unless all or part of it is kept for some reason.
Tokens, stamp and vouchers with no fixed value
The supplier should treat tokens, stamps and vouchers that have no fixed value as a supply for GST purposes at the time a customer buys them. This also applies to postage stamps and vouchers sold to a non-resident for services performed in New Zealand. The supplier has to account for GST on these items when the customer buys them.
Tokens, stamps and vouchers with a fixed value
For tokens, stamps and vouchers with a fixed value, the supplier has a choice of when to account for GST. As it may be impractical to return the GST at the time when the customer buys a voucher, the supplier can return the GST when the customer actually exchanges the voucher for the monetary value of the goods or services purchased. The supplier of the voucher and supplier of the goods or services need to agree to do this.
Claiming GST on tokens, stamps and vouchers
Buying tokens, stamps and vouchers can be claimed as an expense when they are acquired, according to your accounting basis.
A petrol station owner sells an oil company's $20 petrol voucher to a customer. The petrol station owner collects the $20 on behalf of the oil company, and forwards that money to the oil company.
The customer gives the voucher to a friend who buys petrol at another petrol station. Here, there is an agreement between the petrol stations to return the GST on redemption of the voucher. The second petrol station tells the oil company they have sold petrol (goods) in exchange for a $20 petrol voucher.
The oil company reimburses the second petrol station owner for the sale, who then accounts for the GST on the $20 by including the total amount of the sale in Box 5 of their GST return.