Debate has begun within the National Party about whether it should support legalising adoption for gay couples.
A remit was passed at a regional conference held in Auckland at the weekend backing adoption for civil union partners.
The National Party's youngest followers - the Young Nats - say the 1955 Adoption Act is out of date are pushing for reform.
The remit was voted on by about 500 National Party members, including Claudette Hauiti who is in a civil union and has three children.
She says the law stops not only civil union couples from adopting, but also prevents grandparents adopting grandchildren.
Activists for the gay, lesbian, transgender and bisexual communities say the development is encouraging, but they are aware it will be a long time before the change is made.
The remit now goes into a ballot and, if drawn out, will be debated and voted on at the National Party's annual conference in July.
Labour's social development spokesperson Jacinda Ardern has a members' bill in the ballot at Parliament that aims to modernise the adoption laws.
Ms Ardern says National, as the party in government, should address areas of the law where there is inequality.
Prime Minister John Key says he is comfortable with gay adoption and would give initial support to a bill should one come before Parliament. However, the matter is not big enough for the Government to put it on its work programme.
The office of Justice Minister Judith Collins says says changes to adoption laws are not a priority at the moment.