The Federal Government has threatened to overturn the ACT's recently introduced civil partnership laws granting same-sex couples the right to legally binding ceremonies, unless ACT Labor and Greens agreed to amendments.

It is the second time in 18 months the Rudd Government has tried to force the ACT Legislative Assembly to water down its civil union laws, having pressured the ACT Government in May last year into removing similar ceremony provisions from its Civil Partnerships Act.

Chief Minister Jon Stanhope met with Federal Attorney-General Robert McClelland for the first time on Monday night since the Assembly passed amendments creating legally-binding ceremonies a fortnight ago.

The laws came into force last week.

While Mr McClelland remained tight-lipped about the meeting, Mr Stanhope said yesterday the Attorney-General made the Commonwealth's position on the recent amendments very clear.

''I have to say, regrettably, the Commonwealth is maintaining its position of opposition ... and they've indicated that it's a position that they won't accept and that they are prepared to intervene to overturn the recent amendments to the civil union legislation in the ACT,'' Mr Stanhope said yesterday.

According to Mr Stanhope, the Federal Government would only allow the laws to stand if the Assembly agreed to amendments ''to remove that element of the civil union legislation that which allows for a civil union to be created through the declaration before a civil partnership notary''.

Mr Stanhope was yet to see the amendments, and he and the Greens said yesterday they would wait until they saw them before deciding whether to accept them. He expected the Commonwealth to allow any ceremonies under the current provisions to stand even if the laws were amended or overturned.

ACT Greens MLA Shane Rattenbury, who introduced the laws with the ACT Government's support, said Mr McClelland's position discriminated against same-sex couples.

''In our view the Federal Government taking this position makes it very clear that they believe same-sex relationships are inferior,'' Mr Rattenbury said.

''This is simply un-Australian, love is love and the Prime Minister should give same-sex couples a fair go.''

Under the Self-Government (ACT) Act, the Commonwealth does not need a reason to disallow ACT legislation.

The Howard Government disallowed a similar Act in 2006, and the ACT Government only passed a watered down version last year after removing legally binding ceremonies to appease the Rudd Government.

Mr McClelland and Prime Minister Kevin Rudd have refused to say whether they will disallow the recent changes..

Mr McClelland's office, which would not answer specific questions yesterday about the meeting, issued a statement saying, ''The Government is committed to ensuring that all couples whether married or de facto do not suffer discrimination. The Government's position is that the most appropriate way to achieve this is through the development of a nationally consistent framework for relationship recognition.''

The Commonwealth has exclusive legislative powers with respect to marriage. But the ACT Government believes the current laws do not contravene the Marriage Act, or the Commonwealth's constitutional rights.

As the Howard government amended the Marriage Act in 2004 to define marriage as only being between a man and a woman, the ACT Government argues there is no legal reason for the Federal Government to overturn the new laws.

This was also the view of constitutional law expert Stephen Gageler, SC, in legal advice to the ACT Government in May last year. Mr Gageler was appointed Commonwealth Solicitor-General, and he would advise Mr McClelland on the legality of the ACT's laws. Mr Stanhope said, ''I don't wish to verbal or embarrass the federal Attorney-General Robert McClelland but he knows in his heart that our legislation doesn't infringe against the Marriage Act.''