A woman is starving herself to death in a Wellington hospital and the Medical Association stands by her choice, saying a doctor's task is not to prevent death but suffering.

Margaret Page, 60, who has been living in Wellington's St John of God care home since 2006, has not eaten for 10 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 them to intervene, the hospital 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 even count as treatment and was outside the realm of a doctor's medical conduct, Ms Briscoe said.

Even though doctors could not assist in suicide, they could give patients painkillers that hasten their deaths. 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 hospital was not doing enough and Auckland criminal defence lawyer Shane Tait told nzherald.co.nz that if a doctor intervened, a conviction was unlikely.

"It would be a very brave jury to convict a medical practitioner in those circumstances," Mr Tait said.

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.

"But Mrs Page isn't that kind of case. It's not an emergency," Mr Dawson said.

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," Mr Dawson said.

Mr Page told Radio New Zealand that his wife was starving herself to death in a "hunger strike" because the hospital would not help walk her to the toilet and would not get her a wheelchair with a seat that did not hurt her.

There had been previous episodes where he had intervened because Mrs Page "didn't want to continue to live", and this time he expected the hospital to do the same, Mr Page said.

Mrs Page was on a waiting list and several months away from getting the things she wanted, 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.

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

"I can undertake to speak to the DHB," Mr La Salle responded.

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

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

Mrs Page had been assessed as capable of making her own decisions, and staff asked her everyday if she wanted to eat, Mr La Salle said.

She had a right to refuse treatment and had clearly indicated she no longer wanted to live, he said.

Mr La Salle denied the hospital was not helping Mrs Page walk to the toilet.

Her daughter has enduring power of attorney but is legally unable to make decisions for Mrs Page unless she is incapable of making them herself.

* Crimes Act Section 41 - Prevention of suicide or certain offences: Every one is justified in using such force as may be reasonably necessary in order to prevent the commission of suicide, or the commission of an offence which would be likely to cause immediate and serious injury to the person or property of any one, or in order to prevent any act being done which he believes, on reasonable grounds, would, if committed, amount to suicide or to any such offence.

- with NZPA