Labour leader Jacinda Ardern says a law-change to take abortion out of the Crimes Act would come down to a conscience vote.
At the Newshub Leaders Debate on Monday evening Ms Ardern and Bill English went head to head with clashing views on abortion law.
Mr English opposes any change to the current law, calling it already "broadly satisfactory".
On Tuesday, Ms Ardern told the AM Show a conscience vote, where MPs can vote based on their views rather than along party lines, would still allow MPs to keep their personal viewpoints.
"It will still be a conscience vote. We'll draft the bill but, for instance, Bill English would still be able to vote with his conscience."
She says she expects some of those within her own caucus would also oppose the bill, but thinks "there will be a majority of parliament that think, actually in 2017, women shouldn't face being criminals for accessing their own rights".
"That doesn't mean it wouldn't have regulation that sits around it but we just don't think it should be in the Crimes Act."
Abortion is a crime in New Zealand, and there are only a few options for women who want an abortion.
Women can obtain an abortion at under 20 weeks' gestation under the following scenarios:
- if the pregnancy is a risk to the physical or mental health of the mother
- if there's a substantial risk that the child would be "seriously handicapped"
- if the child is a result of incest
- if the women is "severely subnormal".