Working Diagnosis.

❍ Field Note

ACC's contested edges

A working GP reading the lines that ACC draws — and three case histories showing where they fall.

ACC is one of New Zealand's most distinctive public institutions. The 1967 Woodhouse Royal Commission set out two principles that still anchor the scheme: community responsibility and comprehensive entitlement [1]. The Accident Compensation Act 2001 operationalises those principles into something far more bounded — cover for personal injury caused by accident, treatment injury, work-related gradual process, and a small number of other defined categories, with a long list of carve-outs [2].

The boundaries do enormous work. They determine whether a back injury after lifting is the community's responsibility or the patient's. Whether a vaginal tear during labour is an accident or biology. Whether a person who develops PTSD after watching their partner die in a car crash gets state-funded therapy or has to fund it themselves.

This is a rough map of where those lines currently fall, and three case histories that show how they get redrawn.

A short list of contested conditions

Where ACC and clinicians most often clash:

  • Pure mental injury. Unless caused by a covered physical injury, a work-related event meeting the strict s21B test, or a Schedule 3 criminal act (mostly sexual offences), it isn't covered [2,3].
  • The accident/degeneration boundary in MSK claims. A shoulder or back that fails during a specific event but is also degenerate on imaging is the daily friction point. ACC can decline if injury was wholly or substantially caused by an underlying condition or aging [2,4].
  • Treatment injury carve-outs. "Ordinary consequence" of treatment, "necessary part" of the procedure, and "underlying health" exclusions still narrow the field [5,6].
  • Surgical mesh complications. Historically declined as ordinary consequence or no causal link; a major reassessment exercise has been underway since 2020 [7,8].
  • Maternal birth injuries before October 2022. Tears, prolapses, and obstetric fistula were excluded because the force was internal to the body. Fixed prospectively in 2022, but not retrospectively [9,10].
  • Babies' birth injuries. Covered only as a treatment injury, not under the new maternal birth injury pathway [9].
  • Long COVID and other infections. Only covered if work-related gradual process can be shown — very hard during community transmission [11,12].
  • Childhood sexual abuse and Loss of Potential Earnings (LOPE). The boundary moved in 2023 with TN v ACC [13,14].
  • Suicide and self-inflicted harm. Generally excluded unless flowing from a covered injury [2].

Three of these are worth a closer look, because they show the system actually changing.

Case 1: surgical mesh and the limits of "ordinary consequence"

Pelvic surgical mesh was offered widely in NZ from the early 2000s for stress urinary incontinence and pelvic organ prolapse. Some women experienced devastating complications: chronic pain, mesh erosion, dyspareunia, recurrent infection. Many lodged ACC treatment injury claims. Many were declined.

Between 1 July 2005 and 25 November 2019, ACC accepted over 1,000 surgical mesh claims and declined 372 [8]. Common grounds for declining included no causal link, no injury, and ordinary consequence of treatment — the last of these reflecting the statutory exclusion that an injury cannot be a treatment injury if it is an ordinary consequence of treatment given the underlying condition and the clinical knowledge at the time [2,5].

In 2019, the Ministry of Health commissioned Victoria University's Diana Unwin Chair in Restorative Justice to run a national listening process. Over 600 mesh-injured people shared their experiences across 32 forums [15]. The resulting report described severe and sustained harm and made 19 recommendations [15].

In October 2020, ACC announced it would reassess every declined surgical mesh claim under updated cover guidance reflecting the latest evidence [7,16]. In August 2023, the Director-General of Health imposed a time-limited pause on transvaginal mesh procedures for stress urinary incontinence, contingent on credentialling, structured informed consent, and a procedure registry being in place [17]. A national Female Pelvic Mesh Service was established to support women with complications [18].

The medicolegal lesson is uncomfortable. The phrase "ordinary consequence" is doing the heavy lifting. What counts as ordinary depends on what the clinical literature says about prevalence, which depends on what's published, which depends on whose harms get measured. When a complication is common but under-recognised, "ordinary consequence" can systematically exclude exactly the people whose injuries the scheme was designed to cover. The restorative justice process was, in effect, the corrective.

Case 2: maternal birth injury and the 2022 amendment

For nearly fifty years, the AC Act defined an accident as requiring an external force [2]. A torn perineum during labour did not qualify, because the force came from inside the body. A pelvic organ prolapse from delivery was, in legal terms, the same as one from chronic constipation. Birthing parents who needed surgery, physiotherapy, or ongoing care for these injuries paid for it privately or went without.

The Accident Compensation (Maternal Birth Injury and Other Matters) Amendment Act 2022 came into force on 1 October 2022 [10,19]. It added a new limb to the definition of accident in section 25(1)(f): an application of force or resistance internal to the human body, from the onset of labour to the completion of delivery, resulting in an injury listed in the new Schedule 3A [10,19]. Schedule 3A contains around twelve injury categories, including anterior, posterior, and uterine prolapse; obstetric anal sphincter injury; obstetric fistula; uterine rupture; pubic ramus fracture; and tears to the perineum, labia, vagina, vulva, clitoris, cervix, rectum, anus, or urethra [10,19].

Three significant exclusions remain.

First, the change is not retrospective. A birthing parent injured on 30 September 2022 has the same status as one in 1985: no cover [10,19]. The select committee process heard from women who would not benefit from their own submissions.

Second, episiotomies and caesarean sections are not covered under the new pathway, because they involve clinical incision rather than internal force. They remain potentially claimable as treatment injuries on the usual criteria [9,10].

Third, standalone postpartum mental injury (e.g. severe PPD or birth-trauma PTSD without a listed physical injury) is not covered. Mental injury can be added consequentially to a covered physical injury, but cannot stand alone [9,10].

The Bill made smaller changes in passing: the threshold for occupational hearing loss dropped from 6% to 5%, and the test for work-related gradual process injuries was clarified to restore the more claimant-friendly standard that existed before 2010 [20]. None of this fixes the gendered structural problem completely — but it acknowledges, after fifty years, that the structural problem existed.

Case 3: TN v ACC and the date-of-injury rule

In 2023, the New Zealand Court of Appeal handed down a decision known as TN v ACC that quietly redrew one of the scheme's most consequential rules [13,14].

TN was sexually abused from the age of two. Her family prevented her from accessing medical care unaccompanied, so she could not disclose the abuse before turning 18. Decades later, her abusers were convicted and imprisoned. She lodged an ACC claim for Loss of Potential Earnings, which compensates someone whose earning capacity was permanently reduced by an injury sustained as a child.

Under ACC's prior interpretation, a LOPE claim arising from childhood sexual abuse required the claimant to have first sought treatment for the resulting mental injury before they turned 18 [14]. TN couldn't meet that test, through no fault of her own. ACC declined.

The Court of Appeal held that the date of injury for these claims is the date of the abuse itself, not the date of first treatment [14]. The decision opened LOPE eligibility to a population previously excluded — survivors who, for entirely understandable reasons, were unable to seek help as children.

ACC estimated that TN, combined with another Court of Appeal decision expanding cover, would add roughly $3.6 billion to its outstanding claim liabilities, contributing to a $7.2 billion annual deficit [13]. As of mid-2025, around 262 people had been accepted for LOPE under the new approach, totalling approximately $50 million [13]. Critics — including TN's own lawyer — have argued ACC has been slow to identify and contact eligible claimants, instead waiting for them to come forward [13].

The ethical core is subtle. A scheme cannot promise comprehensive entitlement and simultaneously make eligibility contingent on a behaviour that the abuse itself prevented. The Court of Appeal didn't expand the scheme; it corrected an interpretation that had narrowed it.

The mental injury frontier

The largest unfinished argument is pure mental injury. Under the current Act, you are covered for mental injury only if it flows from a covered physical injury, arises from a Schedule 3 criminal act (mostly sexual offences), or meets the narrow test for work-related mental injury under section 21B [2,3].

Outside those three windows, nothing. A bystander to a fatal car crash develops PTSD and is unhurt physically — no cover [3]. A parent whose child dies in an accident in front of them — no cover, except for any physical injury they suffer themselves [3]. A nurse off-duty witnesses a violent assault and develops a recognised mental injury — no cover, because the trauma wasn't work-related under s21B [3]. The 2014 High Court decision in Toomey v ACC, involving a self-employed worker who assisted with the Christchurch earthquake recovery and witnessed multiple deaths, illustrated how strained the boundary becomes when interpreted strictly — and how much hinges on employment status [3,21].

There are principled defences for the line where it sits. ACC is an accident scheme, not a general welfare scheme. Mental health support is provided through the public health system. Expanding cover would significantly expand levies. There are also principled critiques. The line between mental and physical incapacity isn't morally meaningful in the way the statute treats it; what matters is whether a person's life has been derailed by something the community arguably has some responsibility for [3].

The shape of it

Each contested condition is, at root, a story about who counts and what counts as an injury worth the community's collective backing. The boundaries are not natural facts. They are choices. The scheme's real test is whether it can revise its own choices when the evidence demands it. Surgical mesh and maternal birth injuries are slow, partial answers in the affirmative. The mental injury frontier is the largest open question, and probably the next one.

For working GPs, the everyday boundaries we push against — the back with concomitant degenerative change, the shoulder we can't quite call traumatic, the treatment injury form for a complication that may or may not be ordinary — are the operational face of these structural choices. The phrasing in our ACC45s does real work. So does the willingness to lodge claims for things that might be declined, because that's how the boundaries get tested.

References

  1. Royal Commission of Inquiry into Compensation for Personal Injury in New Zealand (Woodhouse Royal Commission). Compensation for personal injury in New Zealand. Wellington: Government Printer; 1967.
  2. Accident Compensation Act 2001 (NZ) [Internet]. Wellington: New Zealand Government [cited 2026 May 2]. Available from: https://www.legislation.govt.nz/act/public/2001/49/latest/
  3. Crawford C. New Zealand's accident compensation scheme — mental injury cover at the margins [LLB(Hons) dissertation]. Dunedin: University of Otago; 2017 [cited 2026 May 2]. Available from: https://www.otago.ac.nz/__data/assets/pdf_file/0033/329757/new-zealands-accident-compensation-scheme-mental-injury-cover-at-the-margins-672766.pdf
  4. Accident Compensation Corporation. Understanding claims and cover [Internet]. Wellington: ACC; 2023 [cited 2026 May 2]. Available from: https://www.acc.co.nz/for-providers/lodging-claims/understanding-claims-and-cover
  5. Oliphant K. Beyond misadventure: compensation for medical injuries in New Zealand. Med Law Rev. 2007;15(3):357–91. doi:10.1093/medlaw/fwm016
  6. New Zealand Government. New ACC treatment injury law fairer and simpler [media release]. Wellington: Beehive.govt.nz; 2005 [cited 2026 May 2]. Available from: https://www.beehive.govt.nz/release/new-acc-treatment-injury-law-fairer-and-simpler
  7. Accident Compensation Corporation. Pelvic mesh injury [Internet]. Wellington: ACC [cited 2026 May 2]. Available from: https://www.acc.co.nz/im-injured/what-we-cover/pelvic-mesh-injury
  8. Al-Azzawi T. Surgical mesh crisis: why have NZ regulators failed to act [LLB(Hons) dissertation]. Auckland: New Zealand Women's Health Council; 2022 [cited 2026 May 2]. Available from: https://www.womenshealthcouncil.org.nz/wp-content/uploads/2022/12/Surgical-Mesh-Crisis-Tamarra-Al-Azzawi.pdf
  9. Accident Compensation Corporation. Maternal birth injuries: information for providers [Internet]. Wellington: ACC [cited 2026 May 2]. Available from: https://www.acc.co.nz/for-providers/provider-contracts-and-services/maternal-birth-injuries
  10. Accident Compensation (Maternal Birth Injury and Other Matters) Amendment Act 2022 (NZ) [Internet]. Wellington: New Zealand Government [cited 2026 May 2]. Available from: https://www.legislation.govt.nz/act/public/2022/51/latest/
  11. Community Law. Conditions caused gradually: covered only if work-related [Internet]. [cited 2026 May 2]. Available from: https://communitylaw.org.nz/community-law-manual/chapter-19-accident-compensation-acc/when-youre-covered-by-acc-and-when-youre-not/conditions-caused-gradually-covered-only-if-work-related/
  12. McConnell G. Long Covid and ACC: the 'appallingly' low number of compensation claims accepted. NZ Herald [Internet]. 2022 [cited 2026 May 2]. Available from: https://www.nzherald.co.nz/nz/long-covid-and-acc-the-appallingly-low-number-of-compensation-claims-accepted/I7VKZMDAQ5AB6TBUC2HW3BMQ4I/
  13. Bradley A. How ACC plans to manage the estimated $3.6b cost of compensation for abuse survivors. Radio New Zealand [Internet]. 2025 [cited 2026 May 2]. Available from: https://www.rnz.co.nz/news/in-depth/569772/how-acc-plans-to-manage-the-estimated-3-point-6b-cost-of-compensation-for-abuse-survivors
  14. Bradley A. Abuse compensation claims has cost ACC $50 million so far. Radio New Zealand [Internet]. 2025 [cited 2026 May 2]. Available from: https://www.rnz.co.nz/news/national/564906/abuse-compensation-claims-has-cost-acc-50-million-so-far
  15. Diana Unwin Chair in Restorative Justice. Hearing and responding to the stories of survivors of surgical mesh. Wellington: Te Herenga Waka—Victoria University of Wellington for Ministry of Health; 2019.
  16. Ministry of Health. Ministry welcomes ACC's offer to reassess declined surgical mesh claims [news release]. Wellington: Ministry of Health; 2020 [cited 2026 May 2]. Available from: https://www.health.govt.nz/news-media/news-items/ministry-welcomes-accs-offer-reassess-declined-surgical-mesh-claims
  17. Ministry of Health. Surgical mesh statement from Director-General of Health [Internet]. Wellington: Ministry of Health; 2023 [cited 2026 May 2]. Available from: https://www.health.govt.nz/strategies-initiatives/programmes-and-initiatives/surgical-mesh/surgical-mesh-statement-from-director-general-of-health
  18. Health New Zealand | Te Whatu Ora. Female Pelvic Mesh Service [Internet]. [cited 2026 May 2]. Available from: https://www.tewhatuora.govt.nz/health-services-and-programmes/the-new-zealand-female-pelvic-mesh-service
  19. Davidson M. Maternal birth injuries [How to treat]. NZ Doctor [Internet]. 2023 [cited 2026 May 2]. Available from: https://www.nzdoctor.co.nz/educate/MBI
  20. Wilson E. Birthing injuries now covered by ACC after passing of new law. Govett Quilliam [Internet]. 2022 [cited 2026 May 2]. Available from: https://blog.thelawyers.nz/family-and-litigation/acc-reform
  21. Toomey v Accident Compensation Corporation [2014] NZHC 1394.

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