Chief Minister Jon Stanhope says he will not back down on gay unions, and has warned his federal Labor colleagues against interfering in the ACT's business.
His strong stance is an early challenge to Prime Minister Kevin Rudd, who does not support gay marriage.
Mr Rudd can use his territory powers to quash the progressive ACT laws, as the previous Liberal administration did twice on ACT gay unions.
But Mr Stanhope made it clear yesterday he would brook no such intervention from the new Prime Minister.
"I expect my colleagues federally to accept [the legislation] ... I have to say I will be deeply disappointed if they don't," he said yesterday.
"We will do what we need to do to have it passed."
Mr Stanhope said he would contact Mr Rudd's office this week to arrange a meeting.
The ACT Government wants to allow ceremonies in which same-sex couples make a legal pledge to each other before an official. Such ceremonies are not allowed anywhere in Australia. Couples could come from other states to marry in the ACT.
Gay lobby groups have warned the bid could fail because Mr Rudd had opposed such ceremonies during the election campaign, saying marriage should be between a man and a woman.
There is a semantic element to the debate. The ACT Government insists its same-sex ceremonies do not constitute marriage because that is a cultural institution for heterosexual couples.
There was speculation the ACT could be forced to water down its legislation to a Tasmanian-style relationships register, a "paper process" with no official ceremonies.
Mr Stanhope said he would do no such thing. The Government had already compromised in redrafting its gay union Bill, the second version of which, called the Civil Partnerships Bill, is tabled in the Legislative Assembly.
"At this stage the Government doesn't intend to reduce its commitment," he said.
"This is about according the same rights to all Canberrans, irrespective of who they are or their sexuality."
Mr Stanhope said Mr Rudd's comments about gay unions had been made in relation to Labor's federal policy platform, which set out the ALP's agenda in Federal Parliament. The ACT was a different matter.
Mr Stanhope said having a Tasmanian-style relationships register would be a further compromise which he was not considering. It was appropriate for the ACT to follow the lead of the world's key democracies in allowing same-sex unions.
Mr Stanhope said the gay union issue was not just about equal rights for same-sex people, it was also about the ACT's democratic right to make its own laws.
His Government was elected on a campaign which included gay unions.
The people of Canberra had the right to decide on their own legislation.
"Any Federal Parliament that feels that they have the capacity to override the democratic right of the people of the ACT really aren't responding as they should to those rights," he said.
Under the Civil Partnerships Bill, which is to be debated in the Assembly next February or March, a same-sex couple can hold a ceremony which creates a legal relationship between them.
They must make a declaration to each other in front of a registered "civil partnership notary" and at least one other witness.
A spokesman for federal Attorney-General Robert McClelland has said the minister would not comment until he had received advice from his department, and met ACT Attorney-General Simon Corbell. That meeting has been scheduled for this week.