The credit is claimed in a return of its own. After the income tax return for the year is filed, the business files an R&D supplementary return within 30 days after the income tax return due date, or the extension of time due date. The supplementary return reports the eligible expenditure for each approved activity, calculates the credit and works out how much is refundable. It is filed in myIR and must be filed by its due date. This page explains what it contains and how it fits with the rest of the process.
What it is
| Element | Rule |
|---|---|
| Purpose | To claim the R&D tax credit for the income year |
| Precondition | General approval or criteria and methodologies approval for the year, and the income tax return filed |
| Deadline | Within 30 days after the income tax return due date, or the extension of time due date |
| Where | The R&D tax incentive account in myIR |
| Contents | Eligible expenditure by approved activity and category, adjustments, the credit at 15% and the refundability calculation |
| Late filing | The return must be filed by its due date |
| Corrections | Within the 4 year time bar, for approved activities only |
Who it applies to
Every claimant, every year. Approval for 3 years does not change this: each income year has its own supplementary return with that year's expenditure. Companies file after the IR4, partnerships and trusts after their own returns, and the credit flows to the income tax assessment for the year.
The return is also where the refundability rules are applied. The business reports its labour-related taxes and other figures the cap depends on, and Inland Revenue calculates how much of the credit above the year's income tax is refunded and how much is carried forward; the refundability page explains the cap.
The return also records the eligibility conditions for the year: that the business carried on business in New Zealand, met the minimum spend or used an approved research provider, and was not an excluded entity. Partnerships and look-through companies report the credit for allocation to partners and owners according to their shares.
How it works
- Close the year's records by approved activity: time, payroll, contractors, providers, consumables, depreciation and overheads.
- Apply the adjustments. Remove ineligible items, cap overseas expenditure at 10% of the total, apply the feedstock rule to goods sold, review any government funding, and confirm the NZ$50,000 minimum and NZ$120 million maximum.
- Reconcile the activity totals to the accounts.
- File the income tax return and note its due date, which sets the supplementary return deadline.
- Complete the supplementary return in myIR: expenditure by activity, the credit, and the refundability inputs.
- File within 30 days of the income tax return due date, or the extension of time due date.
- Keep the workpapers; Inland Revenue may ask for them before or after paying the credit.
Because the deadline runs from the return due date rather than the filing date, a business can file its income tax return early and still have until 30 days after the due date to file the supplementary return. Most businesses file the two together.
Worked example
Illustrative example. Manawatu Robotics Limited, a hypothetical company with a 31 March 2026 balance date, general approval for two activities and a tax agent with an extension of time.
| Item | Activity 1 (core) | Activity 2 (supporting) | Total |
|---|---|---|---|
| Employee remuneration | NZ$420,000 | NZ$80,000 | NZ$500,000 |
| Approved research provider | NZ$60,000 | NZ$60,000 | |
| Consumables and depreciation | NZ$45,000 | NZ$15,000 | NZ$60,000 |
| Overheads, apportioned | NZ$30,000 | NZ$10,000 | NZ$40,000 |
| Eligible expenditure | NZ$555,000 | NZ$105,000 | NZ$660,000 |
| Credit at 15% | NZ$99,000 |
Manawatu files its IR4 on 20 March 2027 and its supplementary return on 15 April 2027, inside the 30 April deadline set by the 31 March extension of time due date. Its income tax for the year is NZ$20,000, so NZ$79,000 of credit is above the tax and is refunded to the extent the cap allows, with any remainder carried forward.
Common questions
Can we file the supplementary return before the income tax return? No. The income tax return comes first.
What if we discover more expenditure later? Request a correction within the time bar, provided the expenditure relates to approved activities.
Is there a paper form? The supplementary return is filed electronically in myIR.
Does a late income tax return move the deadline? No. The 30 days run from the due date, not the filing date.
Can an adviser file it for us? Yes, a tax agent or other authorised person linked to the business in myIR can file the supplementary return, although the business remains responsible for its accuracy.
Does the return need attachments? No. It is a structured form in myIR; keep the workpapers and records for review rather than attaching them.
What if an approved activity had no expenditure this year? Report it with nil expenditure, or omit it; approval is not lost by a year without spend, but a later year's spend still needs the approval to cover that year.
Related pages
Official sources
Educational content only, not tax advice. See the disclaimer.