Filing your income tax return in New Zealand on myIR: who must file, the tax year and deadline, what documents you need, and what happens if you are late.
Salary earners are usually auto-assessed; anyone with untaxed income over $200, self-employed people and companies file an IR3 or IR4.
Tax year and deadline
Tax year 1 April to 31 March; returns are due 7 July, or 31 March the following year with a tax agent.
Penalties for filing or paying late
Inland Revenue gives 30 days' notice before charging a late filing penalty on an income tax return, and no penalty applies if the return is completed in that time. The penalty depends on net income: $50 if it is under $100,000, $250 from $100,001 to $1 million and $500 above $1 million. Late payment penalties are charged in stages: 1% on the day after the due date, a further 4% on the remaining tax and penalties on the 7th day, and for taxes other than GST and income tax (including provisional tax), 1% for each further month. A first late payment within a 2-year period may get a grace period. Use of money interest is charged on top, calculated daily.
Written from published tax-authority guidance and reviewed on 2026-10-11. Everything here is indicative rather than a ruling on your circumstances, and rules change. Confirm anything you rely on with Inland Revenue (IRD) before acting on it, and tell us if you find something out of date so we can correct it.
This guide explains the rules in general terms and is not tax advice for your circumstances. Confirm your position with a qualified adviser or with Inland Revenue (IRD).