The Two GST Dates That Catch Out Most New Zealand Businesses
GST is due the 28th — except for the November and March periods, which are not. Plus how provisional tax and use-of-money interest actually interact around a 31 March balance date.
New Zealand GST returns are due on the 28th of the month after the taxable period ends — with two exceptions that cause most of the late filings. The period ending November is due 15 January, and the period ending March is due 7 May. Those two dates account for more penalties than the other four combined, because they break the pattern people have learned.
NZ GST is due the 28th, except: the November period is due 15 January, and the March period is due 7 May.
The standard two-monthly cycle
Most New Zealand businesses file GST two-monthly. Registration is required once taxable supplies exceed NZ$60,000 in any 12-month period, looking both backwards and forwards — if you expect to cross it in the coming year, you register before you do, not after.
- Period ending 31 May → due 28 June
- Period ending 31 July → due 28 August
- Period ending 30 September → due 28 October
- Period ending 30 November → due 15 January (not 28 December)
- Period ending 31 January → due 28 February
- Period ending 31 March → due 7 May (not 28 April)
Provisional tax, and why the interest surprises people
Under the standard option, provisional tax instalments for a 31 March balance date fall on 28 August, 15 January and 7 May. You are paying this year's tax during this year, based on last year's liability uplifted.
Use-of-money interest is what catches growing businesses. If your actual profit runs well ahead of the prior year, the standard-option instalments under-pay, and Inland Revenue charges interest on the shortfall from the relevant instalment date — not from the date you eventually discover it. A business that doubles revenue can find itself paying interest on money it did not know it owed.
Use-of-money interest accrues from the instalment date, not from when you find out. Growing fast is precisely what triggers it under the standard option.
What actually prevents it
Forecasting, not filing. The compliance work is straightforward; the value is in knowing the number before the date arrives.
- Maintain a rolling profit forecast so the instalment can be sized against reality rather than last year.
- Review the estimate before each of the three dates, not after the year end.
- Consider whether the estimation option or tax pooling suits a business whose profit is genuinely volatile.
- Reconcile GST monthly even when filing two-monthly, so the return is a formality rather than a scramble.
Zero-rating and imported services
Exported goods and services are generally zero-rated: you charge 0% GST but still claim input credits on your costs. That is favourable, and it is also one of the most common places we find coding errors during a cleanup — zero-rated and exempt get conflated, and the input credit position ends up wrong.
Imported services can trigger a reverse-charge obligation for businesses making exempt supplies. If you buy significant services from overseas and your own supplies are not all taxable, that is worth checking specifically.