You're likely to be charged GST on most supplies you purchase for your taxable activity. As a GST-registered business, you are able to claim back the GST you have been charged on goods and services used in your taxable activity. The amount of GST you have claimed (input tax) is subtracted from the amount of GST you have charged (output tax) to calculate your tax to pay or GST refund.
What can be claimed
Most of the time, claiming GST will be easy. You can claim the amount of GST shown on the invoice provided with the goods and services you bought for use in a taxable activity. For supplies costing more than $50, you must hold a tax invoice when you claim the GST on your return.
If you've bought goods from overseas, the supplier probably will not charge you GST unless they carry on a taxable activity in New Zealand.
When you import the goods, you'll likely be charged GST on them by Customs as they come into New Zealand. You can claim this amount back if you are GST registered and are using the goods solely to make taxable supplies.
Buying from non-registered suppliers
If you buy goods or services from an unregistered person, you won't be charged GST. This normally means you won't be able to claim GST on the purchase. For some special supplies, such as secondhand goods, you may still be able to claim GST.
You can only claim GST on goods and services used in your taxable activity to make taxable supplies. For supplies that are partially used privately or to make exempt supplies, you will need to estimate the percentage of the goods and services used for taxable activities. This estimation should be made when you first acquire the goods or services, and must be fair and reasonable.
You can claim a percentage of the GST equal to the percentage of the goods or services used for taxable activities.