MPs have voted to put the End of Life Choice Bill to a public referendum.
It was a tight result in Parliament on Wednesday night, with 63 in favour and 57 against.
David Seymour, ACT leader and architect of the Bill, says it is great news.
"New Zealanders will actually get to ratify a law that Parliament makes and test it for themselves, so I think that's quite a big development."
New Zealand First previously said it wouldn't support the legislation further if the decision wasn't put to a referendum.
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Seymour says it's important people have their say, and is adamant a majority of the public will back it.
"It also significantly increases the chance that the Bill will pass through Parliament - New Zealanders will ultimately have the choice of assisted dying if they are suffering at the end of their life."
The Bill still needs to pass its third reading next month.
"Securing NZ First's nine votes by having a referendum certainly makes it a lot more likely that the Bill will pass through Parliament," said Seymour. "According to Newshub's polling, almost three-quarters of New Zealanders favour this choice."
A Newshub-Reid Research poll last year found 71 percent of Kiwis in favour of euthanasia.
End Of Life Choice Society president Mary Panko says Wednesday night's vote in Parliament is exactly what she was hoping for.
"It's a safety net - it allows people to make the choice themselves. I think it's amazing that the MPs who are opposed to the End of Life Choice [Bill] are busy telling us that New Zealanders can't understand what they are voting for."
She says the referendum - expected to be held at the 2020 election - can't come fast enough.
"We have friends and members who are desperately ill right now. It's going to put the whole thing off - a year before the referendum, followed by a year before the thing comes into practice - so you know, it is going to be a great delay."
The question, put forward by NZ First, will be: "Do you support the End of Life Choice Act 2017 coming into force?"
Kiwis will also get to have their say on cannabis use at the 2020 election, expected to be held nearly a year from now.