Who must file an income tax return in New Zealand, the tax year and deadline, what documents you need, how to file with Inland Revenue (IRD), and what happens if you are late.
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Updated for 2026
Last reviewed September 2026
Who must file
In most countries, anyone with income above the tax-free amount who was not fully taxed through payroll withholding must file: the self-employed, landlords, company directors and anyone with more than one income source. Companies file their own return. Check Inland Revenue (IRD)'s rules for employees, who are sometimes exempt or auto-assessed.
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
Every country fixes a tax year and a filing deadline a few months after it ends. Inland Revenue (IRD) publishes both. Put the deadline in your calendar with a reminder a month before, because late filing is penalised even when no tax is due.
Tax year: 1 April to 31 March.
Tax year 1 April to 31 March; returns are due 7 July, or 31 March the following year with a tax agent.
What you need
Your IRD number and login for Inland Revenue (IRD)'s online service.
Employment income statements from each employer showing pay and tax withheld.
Your invoices, bank statements and expense records if you are self-employed.
Certificates for pension contributions, insurance, donations and other reliefs you will claim.
Last year's return, to check nothing is missed.
Filing step by step
Log in to Inland Revenue (IRD)'s online service on myIR (Inland Revenue) and open the return for the year.
Check any pre-filled income against your own records and add anything missing.
Enter business income and allowable expenses, then reliefs and deductions with the supporting figures.
Review the calculation, submit, and save the acknowledgement. Pay any balance by the payment deadline.
Employees and salary tax
Employers in New Zealand withhold income tax from salaries under the 2025 bands and pay it to Inland Revenue (IRD). The New Zealand salary tax calculator shows the tax and take-home for any gross salary, which is a quick way to check your payslip before you file.
If you are late
Late returns attract a fixed penalty and late payment attracts interest, both set by Inland Revenue (IRD). File even if you cannot pay in full; penalties for not filing are usually heavier than for paying late, and most authorities allow instalment plans.
Questions people ask
Do I need to file if my employer already deducted tax?
It depends on New Zealand's rules. Some countries require every taxpayer to file, some auto-assess employees, others exempt employees with a single employer and no other income. The rule for New Zealand is set out above.
What if I had no income?
If you are registered with Inland Revenue (IRD), you may still have to file a nil return. Failing to do so is treated as a late return in many countries.
Can I file late without a penalty?
Rarely. Some authorities allow an extension if requested before the deadline. Otherwise file as soon as possible; penalties often grow with time.
Should I use an accountant?
If you are employed with no other income, the online service is designed for you. If you run a business or have foreign income or property, an accountant usually saves more than the fee.
Written from published tax-authority guidance and reviewed on 2026-09-03. 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).
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