A High Court judge has ruled that the abortion law is being used more liberally than Parliament intended.
In a review of the workings of the Abortion Supervisory Committee, initiated by Right To Life New Zealand, Justice Forrest Miller said there was a reason to doubt the lawfulness of many abortions.
Jusice Miller was delivering his judgment following a hearing at the High Court at Wellington in April.
Right to Life had claimed the Abortion Supervisory Committee had failed to properly interpret the Contraception Sterilisation and Abortion Act, so "full regard is given to the rights of unborn children".
It sought to find the committee had failed its statutory duty to review the procedure for abortions and enquire into the circumstances in which consultants authorised abortions on mental health grounds.
It said the committee had failed to seek proper information on the mental health grounds from consultants.
It also sought to find the committee had failed in its duty to ensure adequate counselling facilities were available.
A registered practitioner can only lawfully carry out an abortion if they act under a certificate issued by two certifying consultants.
The Abortion Supervisory Committee said it had no power to "review or oversee the clinical decision-making process".
It denied New Zealand had "abortion on request", and said there was no evidence of this.
In his judgment Justice Miller found the Abortion Supervisory Committee had applied the abortion law more liberally than Parliament had intended.
"There is reason to doubt the lawfulness of many abortions authorised by certifying consultants," he said.
Justice Miller said the abortion law neither "confers or recognises" a legal right to life of the unborn child.
However, he said the Bill of Rights, through the abortion law, had recognised the unborn child had a "claim on the conscience of the community, and not merely that of the mother".
The legislation recognised consultants could certify abortions "only where they believe, in good faith, that continuance of the pregnancy would result in serious danger to the mother's life or health".
Justice Miller ruled the committee had comprehensive standards for counselling.
"I conclude that the legislation does not require that counsellors be independent of licensed institutions."
Justice Miller said the committee recognised counsellors should have a recognised qualification and should participate in regular supervision.
It also recognised that information should be provided to women about the options available, and that counsellors should be able to refer women to other agencies and counselling services.
Justice Miller said as Right To Life had succeeded in part to their claim, they were entitled to costs.
Right To Life and Family First today welcomed the decision.
"It is the most important development in abortion law in New Zealand in the last 30 years," Right to Life spokesman Ken Orr told Radio New Zealand.
He said the court acknowledged that "we have abortion on demand in New Zealand".
Mr Orr said Parliament needed to give legal recognition to the unborn child - as a human being with human rights.
"We would like to see greater protection to the rights of unborn children."
He said if the judgment was upheld then there would be a "substantial reduction of abortions in New Zealand".
Family First national director Bob McCoskrie said the Abortion Supervisory Committee's "lack of supervision and inaction" had led to abortion on demand.
"As a result, approximately 18,000 abortions are performed every year, and since 1991, the number of 11 to 14-year-olds having an abortion has increased by 144 per cent.
"The number of abortions for 15 to 19-year-olds has increased by 74 per cent."
Mr McCoskrie said each week, almost 80 teenagers had an abortion.
Women's National Abortion Campaign spokeswoman Di Cleary said a decision to abort should be up to the woman, and trying to legally enforce the rights of an unborn child would result in women being treated like children.
"That would be horrendous. That would be bringing back a society, I think, most people thought had gone," she told Radio New Zealand.
"Right to Lifers really have to look at their own harassing techniques, they'd do anything and they privilege the foetus before women."
Family Planning chief executive Jackie Edmond said it was hard to see what the impact of today's High Court ruling would be at this stage, but that Family Planning was concerned about any decision that might slow the process for women.
"The reality for us is that the two certifying consultants are two more barriers for women and if there are extra restraints put on some of the ground that could make it even more time consuming and difficult for women."
Ms Edmond said abortion laws were outdated and did need looking at, but that today's ruling was not being looked at by Family Planning as a victory of any sort.
"We're disappointed with this judgment because the Right to Life organisation is really trying to restrict access to abortion. This is their motivation and that is not something we support."