The Care Alliance has told a health select committee legalising euthanasia and assisted suicide is unnecessary and dangerous.
The committee has heard a second round of submissions on legislation to permit medically-assisted dying, "in the event of a terminal illness or an irreversible condition that makes life unbearable".
Former Labour MP Maryan Street proposed and championed the End of Life Choice Bill, along with Matt Vickers, partner of Lecretia Seales who died from a brain tumour after campaigning for the right to die.
"We know not all deaths are good deaths but we believe we can improve services available to the terminally ill. Moving the bright line of prohibition on assisted suicide would create more problems than it would solve," the Care Alliance, a group made up of palliative care doctors and nurses and Hospice New Zealand, said.
Secretary Matthew Jansen said euthanasia and assisted suicide are unnecessary because palliative care works to alleviate the suffering of patients - "physically it works well".
Mr Jansen says more New Zealanders should get better access to higher quality services, but "we should never throw up hands and say 'we can't give you a perfect outcome, therefore we'll give you a lethal injection'. [That's] dangerous."
"We have a serious problem with suicide in this country, particularly among young people, Maori and older men. Our youth services are stretched beyond breaking point and it's a disgrace.
"We think it would be unconscionable for Parliament to give any suggestion to young people that suicide is a proper and approved response to suffering."
Dr Stephen Child, chairman of the New Zealand Medical Association, told the committee "in principle and practice we do not support a change in legislation".
"We completely respect patient autonomy, but it needs to be rational, fully informed, and without coercion. Decisions are often influenced by fear and circumstance which can affect decision-making. Decisions can fluctuate but this is irreversible.
"There are also clinical challenges - 10-15 percent show diagnoses are incorrect. Three percent of cancer diagnoses are incorrect. We are not always right in prognoses; our ability to predict is poor," he says.
"A patient's capacity can be changed by brain metastases or drugs. Can you write a law to 100 percent protect the vulnerable?"
He said it's very difficult to determine what rational and irrational suicides are.
"We believe in right of patients to have treatment withheld and prescribing of analgesics to relieve pain and suffering, even if that may hasten death, but we don't support this law change."
The Medical Association represents the views of more than 5000 medical staff.
The Morgan Foundation told the committee it believes in choice within a regulated framework, "unless you have a very good reason to remove that choice".
"If you don't allow assisted dying what is the alternative? It's nil-by-mouth and it's not pleasant.
"The numbers that would be taken up by this option would be very small but that doesn't mean we shouldn't grant it."
Others making submissions included Dr Khalid Sandu, medical doctor and chair of the Interfaith Council, who said we have a responsibility to make the terminally ill comfortable but not to allow them to take their lives.
He cited the case of an 80-year-old diabetic man in poor health who was twice rushed to hospital with low blood sugar.
"He raised his finger and said 'don't you do anything about it'. I did as he wished, left his flat, and he passed away that afternoon. This is an excellent example of palliative care with compassion."
Green MP Kevin Hague, who is on the committee, said many of the submissions opposing assisted suicide came from those with a religious faith.
He asked Dr Sandu: "Is it your belief that a life belongs to God and therefore he decides? And should that shape New Zealand law?"Dr Sandu replied: "50 percent of people in the last census said they were religious, so yes it should be taken into account".
Wendi Wicks and Robyn Hunt from 'Not Dead Yet' opposed assisted suicide on behalf of the disabled, saying attitudes are inherently negative towards the disabled and that "people say our lives are suffering. We don't want legislation that says our lives are inherently worthy of dying".
They said the disabled make up 24 percent of the population and are New Zealand's largest minority.
"Eugenics under the Third Reich killed 6000 disabled people. It casts a long shadow when people say impairments we live with and live with well are worthy of dying."
Ms Hunt said there have been cases where 'do not resuscitate' has been put on a patient's record without their knowledge.
"It's not the answer to disability, even when degenerative. They want access to good lives before a good death. Suicide data on the disabled is not gathered and there are no suicide prevention services for the disabled."