A retired professor with more than four decades of medical practice as a geriatrician and terminal care manager says he has grave concerns for the future if voluntary euthanasia is legalised.
Dr David Richmond, professor emeritus of geriatric medicine at the University of Auckland and founder of the HOPE Foundation for Research on Ageing, said he would never support medically assisted dying, even in the most difficult of circumstances.
"The reason is not because I'm pig-headed or because I don't have any empathy for those who are in difficult situations.
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"We don't need it; if you talk to the bulk of our palliative care positions they will tell you they can manage even the most difficult illness or disability."
Richmond said proponents were failing to take responsibility for the long term issues associated with medically assisted death.
"Although within the first year of legalising euthanasia it may be looked at as being okay with no problems, by the time you get to eight to 10 years out it begins to create the most horrendous problems, not only to the medical profession but society as a whole."
His biggest concern was that doctors and nurses would become too relaxed about the due processes in place and end the lives of those who either didn't want euthanasia or weren't eligible.
"A person might have a severe disability or illness which qualifies him or her for euthanasia but what do you do about the next person comes along who has not quite got the same symptoms and signs as earlier ones but is also demanding euthanasia?
"Over a period of time you get this thing called incrementalism, gradual development where what started as a small issue become a major issue in society."
He said in some parts of the world that had legalised euthanasia, such as the United States, Belgium and Holland, around half of all deaths were now at the hands of doctors.
Older people were at risk of agreeing to things they didn't want, an issue of particular concern regarding the ageing population, Richmond said.
"A lot of older people are vulnerable to the suggestions that they've had a good enough innings and they're inclined to be persuaded by arguments of that sort.
"They don't want to be a responsibility for their family or take up a lot of money from the government."
Medical professionals were also at risk of making mistakes which could form the basis of a case for voluntary euthanasia, he said.
The doctor recalled one case in his career where a patient diagnosed with stomach cancer wasn't deteriorating at the rate expected.
He checked over the man's medical notes to find that a biopsy of his stomach mass hadn't been done and went ahead with one to find that mass was in fact an ulcer, not cancer.
"So we had to tell the gentleman that he wasn't going to die after all; he wasn't pleased about that because he had made all these dispositions, given away all his stuff and here we were telling him he wasn't going to die after all.
"If that man had wanted euthanasia instead of having us looking after him he wouldn't be alive to tell that story today."
He acknowledged the difficulties faced by patients and their loved ones when they were in pain but said improved palliative care, medicine management and personal support could improve the quality of the final stage of their life.
"I can remember as a medical student noting the difference between the senior doctors who sat down beside their patient's bed and took their hand and spoke to them as a person and the senior doctors who poked their nose through the curtain to say hello and then beetled off to talk to the team."
Richmond said he ultimately believed assisted death was "a very crude approach" to medicine.
"You have to ask the question that why is it that some people want to overturn it now when we've got better methods of treating all sorts of illnesses than we ever had in the past?"