ACC Treatment Injury Cover NZ (2025): Surgical Mishaps and Where Income Cover Steps In

ACC treatment injury cover in NZ: what surgical and medical harm is covered, what's excluded, how weekly compensation works, and where income protection fills the gap on a long recovery.

If a surgery or medical treatment goes wrong, ACC may step in. It is one of the less understood parts of the scheme: it sits in an awkward space between "accident" and "complaint", and what ACC covers here is narrower than people expect. This article explains what an ACC treatment injury is, what is covered and excluded, how income support works, and where private income protection fills the gap when a recovery runs long.

It is general information, not advice about your situation, but it should help you ask the right questions before an operation.

What is an ACC treatment injury?

TL;DR: A treatment injury is harm caused by medical or surgical treatment that is not a necessary part or normal side-effect of that treatment. ACC covers it on a no-fault basis and pays weekly compensation of up to 80% of pre-injury earnings after a one-week stand-down. It does not cover the underlying illness, and income protection is what covers a long recovery that ACC's rules cut short.

A treatment injury is a personal injury suffered while you were seeking or receiving treatment from one or more registered health professionals, where the treatment itself caused the injury, and the injury is not a necessary part or an ordinary consequence of that treatment ¹.

ACC sets three tests. For cover, the harm must meet all three ¹:

• the treatment directly caused the injury;
• a registered health professional was treating you (or you were treated at their direction); and
• the injury is not a normal side-effect or expected outcome of that treatment.

"Registered health professional" is a wide group, covering surgeons, GPs, nurses, dentists, midwives, physiotherapists and others. The cover is no-fault, which matters a great deal and is covered further down.

What types of medical and surgical harm does ACC cover?

In broad terms, ACC covers avoidable harm the treatment caused, rather than the natural course of the condition being treated. That can include harm from a procedure, a delay, a misdiagnosis, an infection acquired through treatment, or the wrong dose of a medicine, provided the three tests above are met ¹.

The line ACC draws is between harm the treatment caused and risk that was always part of the treatment. The table below illustrates that distinction, and is not a substitute for ACC's own assessment of a specific claim.

Figure: Treatment injury, covered versus excluded

Source: ACC, illustrative. Cover depends on ACC's assessment against the statutory tests ¹².

The key idea is that "something bad happened" is not the test. The test is whether the treatment caused harm that was not a necessary part or ordinary consequence of it.

What's excluded, like ordinary risks and the underlying condition?

Two exclusions catch most people out ².

First, ACC does not cover an injury that is a necessary part or ordinary consequence of treatment, meaning a normal side-effect. Many procedures carry expected outcomes, such as scarring, soreness, or a known and accepted risk that materialises. If the outcome was an ordinary consequence of properly delivered treatment, it generally is not a treatment injury.

Second, ACC does not cover an injury that is wholly or substantially caused by your underlying health condition rather than by the treatment. If your condition was always going to deteriorate, and it did, that deterioration is the illness running its course, not a treatment injury. ACC covers personal injury, not illness, and this exclusion keeps the two apart.

That second exclusion connects to a much bigger gap. ACC does not cover illness, disease or most gradual-process conditions at all ⁹. So if the problem you went in for keeps you off work, rather than a discrete treatment injury, ACC is generally not the scheme that helps. That is the territory covered in [off-work for illness, not injury](off-work-illness-not-injury-income-cover-nz).

How is income supported during a treatment-injury recovery?

If a treatment injury is accepted and it stops you working, ACC weekly compensation can apply in the same way it does for any other covered injury. It pays up to 80% of your pre-injury gross earnings while you are unable to work ⁴. The detail of how that is calculated and capped is in the next section.

The practical point is that acceptance comes first. ACC has to accept the treatment injury claim, which takes time and assessment, before income support begins. During that period your sick leave, annual leave or savings usually carry the household. A long surgical recovery, or a disputed claim, is exactly where the timing gets uncomfortable.

Why treatment injury isn't the same as a complaint or negligence claim

This is the part that surprises people most. ACC treatment injury cover is no-fault ³. You do not have to prove that the surgeon or hospital did anything wrong. You only need to establish, on the balance of probabilities, that the treatment caused the injury and that it meets the cover tests ³.

That makes it a different thing from:

• a complaint to the Health and Disability Commissioner about the standard of care; or
• a civil negligence claim seeking compensation for fault.

You can pursue an ACC treatment injury claim without alleging anyone was negligent, and ACC may accept cover even where care was entirely reasonable but harm still resulted. The flip side is that ACC cover is about your injury and rehabilitation, not about holding a provider to account. Those are separate processes, and one does not depend on the other.

How does ACC weekly compensation apply here?

Weekly compensation for an accepted treatment injury follows ACC's standard rules. The headline figures, as they stood at the start of March 2025, are below.

ACC pays up to 80% of your pre-injury gross (before-tax) earnings, and you usually become eligible from day 8, after a one-week stand-down ⁴. What happens in that first week depends on how the injury arose ⁵:

• for the first week of a non-work injury you generally receive nothing from ACC or an employer; while
• for a work injury, your employer must pay 80% for that first week, then ACC weekly compensation begins.

The calculation is also staged ⁶:

• for the first 4 weeks, it is 80% of your average weekly earnings in the 4 weeks immediately before the injury (the short-term rate); then
• after 4 weeks, it is based on 80% of your earnings over the year before the injury (the long-term rate).

Two figures there deserve a note. The maximum of $2,360.72 a week was the cap in effect for the year to 31 March 2025; ACC has since confirmed it rose to $2,418.55 from 1 July 2025 ⁷. The minimum full-time rate of $752.00 a week took effect from 1 April 2025, after this article's date, with a lower minimum applying beforehand ⁸. ACC indexes both each year, so always check the current figure.

The maximum matters for higher earners. Because ACC caps weekly compensation, income above the level that produces the cap is not replaced at 80%, which is one of several limits set out in [why ACC is not income protection](acc-is-not-income-protection-five-limits-nz).

Where does income protection fill the income gap?

Income protection insurance pays a monthly benefit when illness or injury stops you working ⁹. It is built to do two things ACC does not.

The first is illness. ACC covers personal injury, not illness, disease or most gradual-process conditions ⁹. If the reason you cannot work is the condition you were treated for, rather than an accepted treatment injury, ACC generally pays nothing, and income protection is what responds.

The second is the shortfall and the timing. Even where ACC accepts a treatment injury, its payment can fall short of your real income above the cap, can stop under ACC's rehabilitation rules, or can take time to be accepted. Income protection can be structured to sit alongside ACC, covering the gap rather than duplicating cover.

Cover can be compared across major NZ insurers, including Partners Life, AIA, Asteron Life, Fidelity Life and Chubb, on definitions and price rather than headline cost alone. Whether a claim is paid depends on the specific policy, so the wording matters as much as the premium.

How do you protect your income against a long surgical recovery?

If you have surgery coming up and you are weighing the income risk, a few practical steps help. These are things to consider, not a recommendation for your situation.

01. Map your sick and annual leave. Work out how many weeks you could cover before any ACC payment or insurance benefit begins.

02. Know whether your worry is the surgery or the illness. A treatment injury may attract ACC; the underlying illness will not. That shapes which cover does the work.

03. Check your wait period. If you already hold income protection, the wait period you chose sets how long the household runs on savings first.

04. Consider fast access to the procedure itself. Health insurance is a separate question from income, and is covered in [the public surgery waitlist and private cover](public-surgery-waitlist-private-cover-nz).

05. Review ACC and income protection together. They are designed to complement each other, and the structure that keeps premiums sensible is usually one that sits on top of ACC for accidents while covering illness in full.

Frequently asked questions

What counts as an ACC treatment injury in New Zealand? It is a personal injury caused by treatment from a registered health professional, where the treatment directly caused the injury and the harm is not a necessary part or normal side-effect of that treatment. All three tests must be met for cover ¹.

Does ACC cover injuries caused by surgery? It can. Avoidable harm a surgery causes may be covered, but a known and unavoidable risk of the procedure, or an ordinary side-effect, generally is not. ACC assesses each claim against its statutory tests ¹².

Do I have to prove negligence to get ACC cover? No. Treatment injury cover is no-fault. You only need to establish, on the balance of probabilities, that the treatment caused the injury. It is separate from a complaint to the Health and Disability Commissioner or a negligence claim ³.

How much does ACC pay while I recover? Up to 80% of your pre-injury gross earnings, usually from day 8 after a one-week stand-down. The maximum was $2,360.72 a week for the year to 31 March 2025 (rising to $2,418.55 from 1 July 2025), with a full-time minimum of $752.00 from 1 April 2025 ⁴⁷⁸.

What if my recovery is from the illness, not a treatment injury? ACC covers personal injury, not illness, disease or most gradual-process conditions. If the underlying condition keeps you off work, ACC generally pays nothing, and income protection is the cover designed to respond ⁹.

Can income protection and ACC work together? Yes. Income protection can be structured to sit alongside ACC, covering illness in full and topping up where ACC's payment is capped or its rules cut support short. Whether a claim is paid depends on the policy terms and your disclosure ⁹.

This article is general information only and is not personalised financial advice. It does not take into account your particular financial situation, goals or needs. Before acting, consider whether it's right for you and seek advice tailored to your circumstances. Craig Smith Business Services Ltd (FSP712931), trading as Smiths Financial, holds a Class 2 licence issued by the Financial Markets Authority and is a member of the Financial Dispute Resolution Service (FDRS). KiwiSaver and insurance figures are set by Government and providers and can change. ACC covers injury but generally not illness; whether an insurance claim is paid depends on the policy terms, conditions, exclusions, stand-down periods, underwriting and your disclosure. Written by Henry Smith, Financial Adviser; reviewed by Craig Smith, Principal Adviser. Last reviewed 4 March 2025.