Cryptoassets are excluded from GST. This means buying and selling cryptoassets is not subject to GST and you do not need to register for GST.
However, GST-registered businesses that raise funds through issuing security token cryptoassets (which have features similar to debt or equity securities) can claim input tax credits on their capital-raising costs.
Examples could include legal fees, exchange listing fees, and costs associated with preparing a product disclosure statement (or whitepaper in the cryptoasset context).
If you receive cryptoassets as payment for goods and services you provide, you still need to charge GST on those goods and services. You'll need to return GST on the value in New Zealand dollars of the amount of cryptoassets that you receive as payment. Normal GST rules apply from there. When you later sell the cryptoassets you received for the payment of goods and services, you do not have to account for GST on the sale of the cryptoasset. However, there will likely be income tax to pay on the sale of the cryptoassets.
If you create and sell non-fungible tokens (NFTs), GST is payable on your sales where the NFTs are sold to someone in New Zealand. If you sell your NFTs to someone outside New Zealand the supply will be zero rated for GST purposes. With blockchain technology, it can be difficult determining the location of the purchaser of the NFTs.
GST and mining
If you're providing a mining service, you're making a supply for GST purposes, so GST applies. However, if the mining service is being provided for a blockchain that exists outside of New Zealand the supply of the mining services is zero rated. You'll have income tax to pay on the profits from your mining activity.