New Zealand First has no plans to call for a referendum on abortion and its MPs have been keeping quiet on which way they will vote on the reforms.
The party has a history of calling for the public to decide on conscience matters but senior MP Tracey Martin said nobody in the caucus has asked for a referendum and there are no plans to table any amendments to Justice Minister Andrew Little's bill.
The legislation, which would remove abortion from the Crimes Act and instead treat it as a health issue, will have its first reading on Thursday and even Mr Little says he has no idea whether it has the numbers to pass.
ACT leader David Seymour, the Greens, and independent MP Jami-Lee Ross are all voting in favour of abortion reform but whether that's enough to get the legislation across the line will come down to which way National and Labour MPs side.
National MP Amy Adams is working with Mr Little to try to get support for the bill on her side of the House.
Last year the Law Commission recommended three options for abortion law reform.
But the government hasn't chosen any of these, instead opting to make abortions available as of right up to 20 weeks of pregnancy, and possible after that if a doctor agrees.
Mr Little thinks that option has the most chance of passing.
"I don't know precisely where the numbers sit on this but I think the bill in the current form it's in gives us the best chance of it passing on Thursday,'' he said.
Unlike David Seymour's End of Life Choice bill where NZ First is voting as a bloc in favour - on the condition a referendum takes place if the legislation passes - MPs will instead treat abortion as a conscience vote.
Ms Martin can't explain why this bill is different or what way her colleagues will vote.
"Because we haven't had any discussion around it I can't explain it because we haven't discussed it. It isn't something that has come up in our caucus at all on this legislation,'' she said.
Ms Martin was reluctant to comment on whether a referendum was off the table because MPs had stronger personal views on abortion.
"I would be reaching and trying to put myself in the mind of my colleagues and I try not to do that.''
Ms Martin was tasked to work with Mr Little to get the bill to a point that best met NZ First's principles of "safe, legal and rare" abortions.
It was her work with Mr Little that reduced the statutory test requirement from the 22 weeks recommended by the Law Commission, down to 20 weeks.
"We basically didn't want the gestation cap to be anymore permissive than what is currently in the Crimes Act so as much as we could we kept the legislation as similar as we could as we shifted it over to the Health Act,'' Ms Martin said.
Several Labour MPs this morning said they supported the Bill.
National Party leader Simon Bridges said he would give his initial support for the abortion legislation to go to select committee, but would push for further safeguards after 20 weeks.
"The position pre-20 weeks of gestation, seems to me, is one where law and practice should match. They haven't and so I accept that [changing it] is the right position."
Mr Bridges said he would be watching very closely to ensure stronger post-20-week restrictions at the select committee.
"I'm very hopeful, in fact I think it's very likely, there will be changes as I'm suggesting."
He said National MPs as a caucus were more split on the topic than Labour.
"My message - whether it's been euthanasia, whether it's been drugs reform, or this - is very clear about that to my Members of Parliament, to also be civil on the way through."
Mr Bridges said he was still looking at the provision that would create a 150 metre "safe zone" where protests could not be held.
"I stand to be corrected but it seems to me we don't have the culture, if you like, that we've seen in other countries like the United States of big protests and that sort of thing so I suppose what I'm saying is I would like to see a case made out for that."
Long, frustrating wait
Five years, ago Amber was 23, and had to deal with an unwanted pregnancy.
It took a month from when she first saw her GP to when the abortion took place.
She said having to wait that long was frustrating and ludicrous.
"During this time I was really really sick ... it was just a sense of feeling I had to validate a decision I'd made for myself to strangers over a lengthy period of time. It was ridiculous,'' she said.
While Amber would like to see the legislation go further, the Voice for Life lobby group has decried the proposed law change, calling it disturbing and radical.
With people on both sides of the debate not prepared to back down, it's now on MPs to choose.