Medical ethics experts have stood by a terminally ill patient's wish to starve herself to death, saying a doctor's task is to prevent suffering and not death.

Margaret Page, 60, who has been living in Wellington's St John of God care home since 2006, has not eaten for 11 days and has drunk only a small amount of water.

She has said she no longer wants to live, and three psychiatric assessments have found her capable of making her own decisions.

Despite her separated husband urging staff to force feed her, the facility is respecting her decision as her right.

Medical Association ethics committee chairwoman Tricia Briscoe said Mrs Page's actions were beyond doctors' responsibilities.

"If the patient has all her marbles, then they have the right to choose what they wish to do in terms of treatment."

Food and water did not count as treatment and were outside the realm of a doctor's medical conduct. A doctor was there to alleviate a patient's suffering, not to ward off death, she said.

But Mrs Page's husband, Barry Page, separated for 12 years, said the facility was not doing enough.

Mr Page told Radio New Zealand that his wife was starving herself to death in a "hunger strike" because the facility would not help walk her to the toilet and would not get her a wheelchair with a seat that did not hurt her. She also wanted "technology" in her room to stave off boredom.

She was on a waiting list for these things and still several months away from getting them, he said.

St John of God was passively supporting her decision, he said.

If Mrs Page was young and fit - she suffered a cerebral haemorrhage 20 years ago and is disabled - society would not put up with it, Mr Page said.

Auckland criminal defence lawyer Shane Tait told the Herald that if a doctor intervened, a conviction was unlikely. "It would be a very brave jury to convict a medical practitioner in those circumstances."

Force feeding Mrs Page would only "technically" be assault. There were enough protections for doctors and for intervening in a suicide attempt that would defend them, Mr Tait said.

The Crimes Act, Section 41, says everyone is justified in using reasonable force to prevent a suicide.

But Otago University Professor John Dawson, an expert in mental health law, told Radio New Zealand that the clause was for emergencies such as someone about to jump off a building, and would not apply in Mrs Page's case.

"It's not an emergency."

The more relevant legal clause was a person's right to refuse treatment, protected in the Bill of Rights, he said.

"It's not illegal or criminal to commit suicide," Professor Dawson said.

The facility's chief executive, Ralph La Salle, was asked on Radio New Zealand whether the facility had made an urgent effort to get Mrs Page bumped up on the DHB's waiting list so she could get what she wanted.

"Everybody in the health system ends up having to wait. That's the health system at this point in time."

The facility had fulfilled all its legal obligations, he said.