Australian advocates for marriage equality have welcomed support from today's federal Young Liberals Conference for a conscience vote for all Liberal senators and MPs, saying it increases pressure on opposition leader Tony Abbott to allow all his MPs to vote according to their personal beliefs.

At the Young Liberal federal conference in Hobart this afternoon a motion from the Victorian division in favor of a conscience vote gained two-thirds support.

The motion read, ‘The Federal Conference calls on the Federal Party to grant it's Members and Senators a conscience vote on same-sex marriage.

A statement of principles on the Liberal Party’s website claims that the party supports ‘the inalienable rights and freedoms of all peoples; and … lean government that minimizes interference in our daily lives.’

‘The Young Liberal motion increases pressure on Tony Abbott to include a conscience vote in this year's Coalition election platform and adds to growing pressure for a conscience vote from within the Coalition and from within Mr Abbott's own family,’ Croome said.

‘If the Coalition is to maximize its vote, particularly among young people, it cannot afford to maintain its blanket opposition to this inevitable and popular reform.’

‘A conscience vote is about personal freedom and marriage equality is about strengthening relationships and families - all things which Liberals should support"

"It was a grass roots movement within the Labor Party that saw it adopt a pro-marriage equality policy in 2011 and now we are seeing a similar Coalition grass roots movement towards a conscience vote."

An Australian Greens bill to legalize same-sex marriage failed to pass in September after the ruling Labor party gave all its members a free vote on the issue but the Opposition did not.

The East Sydney branch of the Liberal Party and the coalition partner NSW Young Nationals have previously endorsed a conscience vote, as have a number of high- profile Liberal members of the Australian Parliament such as Joe Hockey, George Brandis, Christopher Pyne, Greg Hunt, Malcolm Turnbull, Simon Birmingham, Russell Broadbent and the New South Wales state premier Barry O’Farrell,

Abbott’s sister Christine Forster is a Liberal Party City of Sydney councilor and an openly lesbian supporter of same-sex marriage.

However Abbott, a staunch Catholic, is taking his party to elections in September with a platform that fails to mention LGBT rights and having pledged to Christian groups that he will oppose same-sex marriage in government.

The most recent Galaxy poll on marriage equality showed 64 percent support across Australia with over 80 percent among young people.

A poll from May last year found that 77 percent of Coalition voters support a conscience vote on the issue and believe it would be ‘a smart move’ for Tony Abbott to allow one.