Marriages will stand in Australian state without contest.
Australia said Thursday it would not overturn laws allowing the first same-sex civil unions, in a surprise move that enshrined gay "marriages" in the country.
Attorney General Robert McClelland said the government had decided not to intervene after the Australian Capital Territory (ACT) agreed to minor changes to its gay union laws requiring couples to register before a ceremony.
The national government has twice quashed the ACT's attempts to instigate legally recognised same-sex unions on the grounds that Australia's marriage law says weddings must be between a man and a woman.
"The discussions between the Australian government and the ACT government about the Civil Partnerships Act were conducted in good faith, and the matter has been resolved satisfactorily," McClelland's office said in a statement.
McClelland, of the ruling centre-left Labor party, overturned a similar bid in February 2008, after an earlier attempt was halted in 2006.
ACT attorney-general Simon Corbell said it was a decisive step for the gay rights movement in Australia, and set an important precedent.
"This now opens the door for other states and territories to follow the ACT's lead knowing the Commonwealth accepts ceremonies are now a legal part of the equation," Corbell said.
"The ACT Labor government is proud of its record of achieving real and meaningful reform for gay, lesbian and transsexual people in the ACT."
Two men took advantage of the laws this week to become Australia's first same-sex couple to hold a legally recognised civil partnership ceremony, 20 years after first falling in love.
"We thought we'd take this opportunity not only for gay couples Australia wide ... but just for human rights," said Warren McGaw of his union to partner, Chris Rumble.
"I think the majority of Australians are behind us."
The ruling party voted in August to uphold Australia's gay marriage ban, but the government has also passed legislation to remove same-sex discrimination from almost 100 national laws including areas such as tax and employment.
