Prime Minister Jacinda Ardern supports ACT leader David Seymour's End of Life Choice Bill, which would give terminally ill people the right to choose when they die.
Parliament's Justice Committee is due to report back to the house this afternoon.
Ms Ardern told media this morning she voted in favour of the Bill at a confidence vote, but it would be up to each individual MP on which way they voted.
"Certainly, I see my view as a personal one and will leave the Labour caucus to make their own decisions," she said.
"This is a deeply personal issue. Some will have strongly held beliefs that will determine their view. My view has always been one that it's not for me to determine the decisions of others.
"I would like others to have their own choice and that means voting in favour of the Bill," Ms Ardern said.
She told media she understood some people are strongly opposed to the Bill, but said "my view is the best way that I can allow people to make their own decisions is actually giving them access to that choice. At the moment there is no access that that choice because of the law.
"I want it to be a personal matter for individuals and their families."
When asked if she thought the Bill would get the backing for it to pass, she said she simply did not know. She said she didn't even know how the rest of her caucus members were voting.
Also speaking with media this morning, Justice Minister Andrew Little said he too supported the Bill and said the report was "one of the best commentaries of a piece of legislation that's come back to the house" that he had seen.
The committee couldn't agree on any substantive changes so it was up to Mr Seymour to persuade enough MPs to back the law change, Mr Little said.
The cut off date for the Bill to make it to a referendum is March next year.