Same-sex-marriage could be legislated within weeks as more Liberal MPs abandon Malcolm Turnbull's plebiscite promise.

Five Liberal MPs including openly gay Brisbane politician Trevor Evans have reignited the push to pass the reforms, which have been in limbo since the prime minister's costly "people's vote" was rejected by parliament last year.

The push has incited ire from within the Liberal ranks as conservatives maintain their commitment for a plebiscite.

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The Australian reports the new push for a conscience vote is an attempt to put the issues of marriage equality to rest once and for all, after the prime minister received a wave of support from the general population.

Liberal backbenchers that expressed their willingness to cross the floor on the divisive issue include Trevor Evans, Tim Wilson, Warren Entsch, Trent Zimmerman and Jason Wood.

A private member's bill drafted by Western Australian Senator Dean Smith is expected to have bipartisan support from Labor and the Greens.

Federal member for Brisbane, Trevor Evans, is among five backbench Liberals in favour of a conscience vote on marriage equality. (AAP)

Yesterday Mr Turnbull said that Liberal backbenchers "had the right to cross the floor".

"It’s always been a fundamental principle in the Liberal Party, and indeed the National Party. So it’s a very different political culture to the very authoritarian and centrally controlled culture of the Labor Party," the PM said.

Five Liberal MPs have rebelled against Malcolm Trunbull's promise to hold a plebiscite on marriage equality. (AAP)

Liberal MP Craig Kelly, Queensland Nationals Senator Barry O’Sullivan, Tasmanian senator Eric Abetz and Victorian MP Kevin Andrews have condemned the rogue backbenchers' actions saying it undermines Mr Turnbull's election promise to hold a plebiscite on marriage equality.

Senator O’Sullivan warned a breaking of the ranks and a conscience vote would destroy any hope of the Coalition being re-elected, News Corp reports.

Liberal backbench MP Craig Kelly has warned his party colleagues not to break ranks and cross the floor. (AAP)