A bill to allow same-sex couples to adopt in New South Wales, Australia, has narrowly passed in the lower house.

It passed a vote 46-44 yesterday, and after amendments were made, passed 45-43 today.

The bill was introduced by independent MP Clover Moore, who agreed yesterday to insert a clause allowing faith-based adoption agencies to discriminate against gay couples.

Another amendment was added today to allow birth parents the right to state their preference that their children are not adopted by gay couples without breaching anti-discrimination laws.

Church groups welcomed the amendments, saying they were necessary to prevent people and organisations being sued for expressing their beliefs.

However, gay rights groups in the state have said they are concerned that the gay community is not being vocal enough in supporting the laws and has urged people to write to their MPs.

The bill will go to the Legislative Council next week.

Last year, the Australian parliament conducted a six-month inquiry into same-sex adoption and found that changing the law would be in the best interests of children.

Same-sex couples in Australia are allowed to foster children, but full adoption rights are only currently available to gay couples in the Australian Capital Territory, Tasmania and Western Australia.