Marriage equality advocates are calling on the federal government to vote on same-sex marriage immediately and avoid an "expensive and divisive" national plebiscite.
The call comes after reports that parliamentary support for same-sex marriage reform has reached "critical mass" in parliament. The shift is said to be placing renewed pressure on Prime Minister Malcolm Turnbull to grant MPs a free vote, rather than spend millions of dollars on a public vote.
Australian Marriage Equality national director, Rodney Croome, said the numbers in parliament were now in favour of same sex marriage.
"This means there's no need for an expensive and divisive plebiscite," he said on Saturday.
"We urge Malcolm Turnbull to bring back marriage equality legislation, allow a free vote and get this done straight away so Australia can move on.
"This is a historic moment in the marriage equality campaign because it is the first time we can be sure reform has the support to pass federal parliament."
According to Fairfax, 76 MPs in the 150-member House of Representatives back reform, and 41 senators are in favour in the 76-seat Senate.
The thin majorities are said to include those who have publicly changed their mind in the last year -- from both sides of politics.
Croome said most MPs had privately indicated their support for marriage reform.
"Among the majority in support are a handful of politicians yet to declare their stance but we're confident from the private conversations they've had with us, local campaigners or party officials that they will vote for marriage equality," he said.
"The majority is slim but support for marriage equality never goes backwards and is likely to increase during a parliamentary vote with both Turnbull and Shorten in support."
The push for change comes after a number of high-profile conservative politicians this week said they would vote against marriage reform in parliament irrespective of the the result of a public vote on the issue.