The ACT will move to allow civil unions after the Greens announced they would support the Labor government in a vote.
With their support, the Civil Unions bill should pass the legislative assembly next week, ACT Attorney-General Simon Corbell indicated at the weekend.
The Greens had previously been unwilling to support ACT legislation for fear it would undermine the campaign for federally recognised same-sex marriage.
The ACT had previously enacted civil union legislation in 2006, but it was overturned by the Howard government that same year.
Ceremonies and celebrants are expected to be allowed as part of the new legislation.
Tasmania has already indicated it will legislate for same-sex marriage this year if there is no change federally.
Last week, a Galaxy Poll commissioned by Australian Marriage Equality found support for gay marriage had risen nationally by two percent to 64 percent in favour.