MPs, including Jacinda Ardern and Simon Bridges, will soon be voting with their conscience again as the Government pushes ahead with proposed abortion law reforms.
A draft law has gone through the Cabinet Committee and the legislation will then be considered by Cabinet, before it reaches Parliament.
The Prime Minister said on Tuesday she does not know how members of the Labour caucus will choose to vote on the issue when it's presented in Parliament.
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"Some drafts have been discussed with members across Parliament - obviously they'll want to see the final legislation, once that process is complete," she said.
"Ultimately, this is a matter for them, and as I say, I hope it's given due consideration - but I don't know how people will choose to vote."
The proposed law changes are based on recommendations from the Law Commission which reported back its advice to Justice Minister Andrew Little in October.
It recommended three options to decriminalise abortion. The current system requires two doctors to agree a pregnancy would put a woman in physical or mental danger.
Of the three options, one would abolish the need for an assessment of the woman altogether. The second option is to have an assessment where a woman would need to prove the abortion is appropriate.
The final option - favoured by the Justice Minister - is to have an assessment, but only for late-term abortions beyond 22 weeks. As it stands, doctors can refuse to administer abortions, in which case women must find another.
The Law Commission has proposed that doctors who do not wish to administer abortions becuase of their conscientious objections would have to refer women to someone else who could provide the service.
Internal Affairs Minister and New Zealand First MP Tracey Martin has been working with the Justice Minister to represent the party's views to move the process along.
"New Zealand First is looking for what it's always looked for in regards to this particular topic, and that's that it's safe and legal and rare," she told RNZ.
When asked why it has taken so long for the legislation to be drafted, Ardern said it's "not unusual" for legislation that's been drafted around "complex issues - particularly conscience votes - to take a little bit of time".
"This is different - it's not a Government Bill - it's a Bill just really open to individual Members of Parliament to choose how they would like to vote."
The abortion reform legislation will need at least 61 votes from MPs to pass its first reading. As a conscience vote, it will be similar to ACT leader David Seymour's End of Life Choice Bill which passed its second reading last month.
National MP Amy Adams - who has openly supported reform - has been working with the Justice Minister to move abortion out of the Crimes Act.
National leader Simon Bridges said he has no issue with that. He said Adams - who plans to retire from politics in 2020 - has every right to express her personal view on the issue.
"The prerogative of each MP to take a position - even a strong one - what matters is that in a party like National there are different views and people are entitled to those views," he said.
"My message to the caucus on this, just as it has been on euthanasia, on cannabis, on a wide variety of conscience issues, is everyone is entitled to their view.
"What's important is that we're civil on the way through with those differences."
A Newshub-Reid Research poll in March found that the majority of New Zealanders want abortion decriminalised.