An investigation has been launched after a complaint was laid about an assisted death in a public hospital.
A family member of the person who died laid a complaint about their experience at the hospital to the Ministry of Health.
The ministry's assisted dying secretariat has upheld the complaint and referred it to the Health and Disability Commissioner, who has begun an investigation.
Further details, including the location of the hospital, were not known. The ministry did not provide further information, and the commissioner's office said it could not comment on an active investigation.
It was one of four complaints in the first five months of the Assisted Dying Service, which came into force in November after a majority of New Zealanders backed legal euthanasia in a public referendum. The three other complaints had been resolved.
The Assisted Dying Registrar's first annual report on the service - which covers the period from November to March - shows that there had been no breaches of the law so far. Aside from the complaints received by the ministry, feedback has been overwhelmingly positive, the report by registrar Kristin Good said.
Patients and family members reported they were happy with the process, with the support from doctors, and the "peaceful" and "dignified" deaths of their loved ones.
End of Life Choice Society president Ann David said she had received glowing reports about the service. She said even patients who were "bitterly disappointed" to not qualify for an assisted death had been counselled "with warmth and compassion" by their doctors.
She told the story of an elderly woman who had not wanted to die in her room in a rest home and arranged to die in a beautiful outdoor setting in the bush.
"Within minutes she fell into a sleep from which she never awoke. She had avoided a prolonged and gruelling death, remaining instead in personal control to the end."
The latest data shows that 400 people have applied for an assisted death up to June, and 143 people have died.
Around 80 per cent of applicants were Pakeha, and more than half were older than 65. The majority of applicants for the service had been diagnosed with cancer.
The number of people having their applications rejected was high by international standards - possibly because of the relatively strict criteria to access assisted dying in New Zealand.
A total of 68 people (17 per cent) were deemed ineligible, more than half of them because they did not have a terminal illness which was likely to end their life within six months.
Act Party leader David Seymour, who led the law change, said the ministry had done an "outstanding job" in running the service so far.
He noted that some applicants had died waiting for approval from the ministry.
"In some ways, they are the most tragic cases. But if nobody died waiting for approval, you might ask if [the process] was going too quickly. And if too many people did, then you might ask if it was too rigorous."
Seymour said the "one big failing" of the law was the decision to narrow its scope to exclude people with "grievous and irremediable" conditions - such as motor neurone disease.
He said he agreed to this amendment to ensure that the law would pass, but still felt people with these conditions should be able to access euthanasia.
The registrar's report said that one of the main themes of feedback to the ministry was that the threshold for accessing euthanasia was too high.
"The legislation is not as enabling as some people were hoping for with the criteria making an assisted death more restrictive than overseas jurisdictions.
"This was coupled with hope for a broadening of criteria over time."
John Kleinsman, a bioethicist at Catholic organisation The Nathaniel Centre, said he hoped that the ministry would collect a broader range of data on assisted dying, including people's reasons for choosing the service.
This could help safeguard against wrongful deaths by helping to identify whether people felt a "duty to die" because they were a burden on family or caregivers, he said.
His main concern was the increasing demands on an underfunded palliative care sector. Demand is projected to rise 50 per cent in the next 10-12 years, and access is uneven depending on where you live.
"It has been well documented that palliative care is grossly underfunded in Aotearoa. The idea that assisted dying will become a solution to a lack of quality end-of-life care is extremely distressing and frankly unethical and undermines the notion of it being a choice."
New Zealanders voted in favour of legalising assisted dying in a public referendum in 2020, with 65 per cent of voters in favour and 34 per cent against.