The Green Party wants to make abortion freely available to women up to 20 weeks pregnant.
At present, a woman needs the approval of two certifying consultants. The doctor performing the abortion has to believe it is immediately necessary to save the life of the patient or to prevent serious permanent injury to her physical or mental health, or has to believe the foetus would have a serious disability.
Women's spokeswoman Jan Logie said it was time for New Zealand to take a more honest approach to abortion and treat it as a health issue.
"The fact that 99 per cent of abortions are approved on 'mental health' grounds and that rape is not grounds for an abortion reveals the dishonesty of the current legislation," she said.
"The Green Party trusts women to make decisions that are best for them and their whanau/family."
Anti-abortion groups were quick to condemn the proposal.
The party's policy would allow women to make the choice up to 20 weeks. Terminations after 20 weeks would be allowed only when the woman would otherwise face serious permanent injury to her health or in the case of severe fetal abnormalities.
The current law, the Contraception Sterilisation and Abortion Act passed in 1977, makes it an offence to perform an abortion without the approval of two certifying consultants, and to perform an abortion without the belief that an abortion is immediately necessary to save the woman's life or prevent serious physical or mental injury.
The Greens' policy would decriminalise abortion. Ms Logie said that would reduce the "stigma and judgment" that surrounds abortion and enable abortions to be performed earlier in pregnancy which was safer for women.
The party's previous policy in the 2011 election was to review abortion services to ensure equity of access for women throughout the country.
It has made the issue a party issue, rather than the conscience issue it is with other parties. In reality, in order for the issue to be reopened by Parliament, a private member's bill would have to be drawn from the ballot, unless the next Government wanted to amend the law and had enough support to get a bill through.
Prime Minister John Key said yesterday: "My view is that the abortion laws are set about the right place."