GST invoicing requirements NZ 2026: the complete guide

New Zealand's GST rules have stayed mostly stable, but IRD's ability to detect errors has improved significantly as they invest in data-matching systems. The result is that mistakes that might have gone unnoticed five years ago are more likely to be flagged today.

This covers every invoicing requirement your business needs to meet in 2026 and what happens when you get it wrong.

GST registration: when it becomes mandatory

GST registration is mandatory when your taxable supplies exceed $60,000 in any 12-month period (looking back or projecting forward). Taxable supplies include most goods and services sold in NZ; there are exemptions for financial services, residential rent, and a handful of other categories.

Once you cross the threshold, you must register within 21 days. Late registration means you're personally liable for the GST you should have collected from the date you should have registered, not from when you actually registered.

The three types of invoices under NZ GST law

IRD recognises different invoice standards based on transaction value:

Simplified invoice (under $50 GST inclusive): A receipt is sufficient. Must show: supplier name, GST number, date, description, and GST-inclusive price with a statement that GST is included.

Tax invoice ($50 to $999.99 GST inclusive): The full tax invoice requirements apply (see below).

Full tax invoice ($1,000+ GST inclusive): All tax invoice requirements plus the buyer's name and address.

Mandatory fields on a tax invoice

Every NZ tax invoice must contain all of the following:

1. The words "Tax Invoice" 2. Supplier's name (legal name or registered trading name) 3. Supplier's GST registration number in XXX-XXX-XXX format 4. Date of issue 5. Description of the supply: specific enough to identify what was provided 6. Quantity or volume of goods/services supplied (required for invoices over $1,000) 7. Buyer's name and address (required for invoices over $1,000) 8. GST amount charged, OR a statement that the price includes GST 9. Total amount payable 10. Unique invoice number (not legally required under the GST Act, but required under income tax record-keeping rules)

What counts as a valid GST number?

Your NZ GST registration number is the same as your IRD number. It's issued when you register for GST through myIR. Format: XXX-XXX-XXX (9 digits, hyphenated).

It must appear on every tax invoice you issue. Displaying it incorrectly, or displaying a number that doesn't belong to you, makes the invoice non-compliant. Your clients cannot claim GST input credits on a non-compliant invoice.

Filing frequency and GST periods

NZ businesses file GST returns monthly, two-monthly, or six-monthly:

Monthly: required if your annual taxable supplies exceed $24 million. Optional otherwise. Best for businesses with volatile cash flow or regular refund positions.

Two-monthly: the default for most businesses. Returns are due by the 28th of the month following the end of each two-month period.

Six-monthly: available if your annual taxable supplies are under $500,000. Simplest option for small operators with predictable income.

Your filing frequency is set when you register. To change it, apply through myIR.

Invoice basis vs payments basis

Invoice basis (default): GST is owed in the period the invoice is issued, regardless of when you're paid. You may owe GST on invoices your clients haven't paid yet. Applies to all businesses.

Payments basis: GST is only owed when you actually receive payment. Available only to businesses with annual taxable supplies under $2 million, and requires an election in myIR.

Record-keeping requirements

GST records must be kept for 7 years from the end of the income year they relate to. Records must be: - Kept in English (or in a form that IRD can convert to English) - Available for inspection by IRD within a reasonable timeframe - Accurate and complete

Digital records are fully acceptable. Scanned copies of paper receipts are fine. Cloud storage (including PayWren) satisfies the accessibility requirement.

Common GST compliance issues

These are the mistakes that come up most often in GST audits:

Claiming GST on non-deductible expenses: entertainment has a 50% limitation for both income tax and GST. Private use of assets and residential accommodation are not fully GST-claimable.

Failing to return GST on associated party transactions: if you supply goods or services to a related party below market value, GST is assessed on the open market value, not the discounted price.

Missing or incorrect GST numbers on invoices: IRD's data-matching systems increasingly cross-reference these, and mismatches trigger flags.

Incorrect treatment of zero-rated supplies: exported goods and services are zero-rated (0% GST), not GST-exempt. The distinction matters for how you report them. Zero-rated supplies still count toward your registration threshold and go in Box 5 of your return.