MPs have been told to put fear and emotion aside and be principled and brave on the question of voluntary euthanasia.
It came as the health select committee began hearing general submissions on a petition about the contentious topic.
The petition from a former Labour MP, Maryan Street, seeks legislation allowing medically-assisted dying where there is terminal illness and unbearable suffering.
Matt Vickers, the widower of lawyer Lecretia Seales, who fought for the right to die with dignity, told MPs today it would give terminally ill patients some control - as his wife wanted - about how they died.
Others, he said, would also get the chance to have honest conversations with their doctor about their death.
But he said it was contentious, and MPs would have to think for themselves, and make the right decision.
"There is a huge depth of feeling in some sectors of society. That depth of feeling is worthy of respect but you must have the forbearance to not let it sway your objective analysis. And the evidence may take you to a position that will require you to be principled and brave."
Mr Vickers said he believed fears that had been fuelled were unfounded.
"I think the risks are mainly insubstantial, based on fear. I think certain groups in New Zealand have been pretty forward in stoking up those fears, I can see that in some of the submissions, but I think those fears are unfounded."
The immediate past president of the Voluntary Euthanasia Society, Jack Havill, said there was no evidence assisted dying would boost suicide.
"There's absolutely no evidence to support this. In fact, there's considerable evidence to suggest that suicide would decrease."
The retired intensive care specialist also criticised the New Zealand Medical Association.
"The NZMA who opposes legalisation represents less than 45 percent of doctors in New Zealand and has not even surveyed their members for an opinion."
Another society member, Carole Sweney, said those who were unwell and suffering needed choices, and advance care directives didn't quite cut it.
"Choices are limited to refuse treatment or to refuse nutrition perhaps. Either of these methods will lead to more harm and suffering before death comes perhaps weeks later."
But Australian and New Zealand Society of Palliative Medicine spokesperson Amanda Landers said palliative care, involving listening, understanding and providing pain relief and whatever else was needed, was a better option.
"What stuffed toy do you want on your bed? You can have as many choices as you like around that, and we work with you to make that possible. It's completely different to drawing up phenobarbitone and injecting it into someone to stop their heart beating."
That led to this question from the Greens' health spokesman, Kevin Hague. "I haven't read in your submission or heard from you today any argument as to why the choice to end one's life and to have assistance in doing so should be denied."
Dr Landers responded people often didn't know the choices they had. "Almost everyone changes their mind in my experience."
Mr Hague: "But the person who doesn't shouldn't have that option?"
Dr Landers: "No, they shouldn't."
The committee has received 21,435 written submissions and more than 1800 people want to speak to it.