The ACT Greens are considering blocking proposed improvements to same-sex civil unions, fearing they could undercut national efforts for marriage equality.
The ACT government will bring forward debate of its legislation to effectively reinstate its original civil union laws, which were overturned in 2006 by the Liberal federal government, who said they were too similar to marriage.
Attorney-General Simon Corbell introduced the legislation in December, but it was put on hold once moves developed in federal Parliament to legalise same-sex marriages.
Those moves now appear unlikely to be successful and the federal debate has been delayed.
Mr Corbell said his bill would fully restore the role of ceremonies and celebrants in civil unions and gives same-sex couples the same rights as people married under the Marriage Act.
While the ACT government wanted same-sex marriage to be legalised federally, it wanted to do as much as it could for same-sex couples in the territory in the meantime.
The legislation will be before the Assembly next month during the last two weeks before the territory's October election.
The Liberals will oppose the legislation, so the government is relying on Greens' support to get it made law.
Greens MLA Shane Rattenbury said the legislation provided some improvements to civil unions.
''But we are concerned that this bill could provide a distraction from the national debate about marriage equality,'' Mr Rattenbury said.
''Certainly some of the community organisations that we have been talking to do have reservations about this ACT bill.''
There was potential for other states, and the federal government, to say the ACT's improved civil unions meant there was no need for marriage equality.
''Whilst the ACT has been strong in moving forward before and has provided welcome leadership, nonetheless there is a tactical question about whether this is the right moment to be providing a potential undercutting of momentum for national movement,'' he said.
The Greens would consult with community groups before making the ''difficult'' decision on whether to support the legislation.
Australian Marriage Equality national convener Alex Greenwich said ACT Labor had played a pioneering role, but debate had moved on from civil unions and same-sex couples wanted the right to be married.