A majority of voters support changing the law to allow gay couples to adopt children, according to the latest Herald-DigiPoll survey.
Labour and the Greens have pushed the rights of gay people as an election issue, but the National Party has sidelined them as not a priority.
Adoption in New Zealand is governed by the Adoption Act 1955, and Labour and the Greens say the law needs an update.
More than half - 54.3% - of the poll respondents said the law should be changed to allow gay couples to adopt children, 38% disagreed, and 7.7% either did not know or refused to answer.
The result is a reversal of an online poll on the Herald website in 2009, when 41% of 7000 voters were in favour of gay adoption, and 59% against it.
Green MP Kevin Hague, who has started a cross-party group to find political consensus on gay issues, said the result was pleasing.
"It's great to see that most New Zealanders now support this, and I'm confident that once it's in place, that majority will increase even more.
"What should be at the centre of adoption laws is putting the interests of the child first. To do that you've got to have all the options on the table."
Neither National nor Labour had shown the political courage to change the law, he said.
Green policy is in favour of gay adoption rights and gay marriage, while Labour's policy is to update the law to effectively make adoption for gay couples legal.
Labour's Auckland Central candidate Jacinda Ardern tried to table a Bill recently to update adoption laws, but it was voted down.
"At the moment, gay individuals can adopt children, but a gay couple cannot. A heterosexual civil-unioned couple cannot adopt," Ms Ardern said. She said it was a cop-out to say it was not a priority.
Mr Hague questioned whether Labour had meaningful policy if its MPs were free to vote as they wanted on social issues.
"Six Labour MPs voted against civil unions, which had been their policy, so we don't know whether Labour would do this."
Act New Zealand leader Don Brash said adoption for gay couples would be a conscience vote for his party's MPs.
