Australian Prime Minister Tony Abbott flagged the possibility of putting a decision on same-sex marriage to the Australian public following the next election, after his conservative coalition government blocked its members from voting in favour of gay marriage.

The decision by Abbott to use parliamentary tactics to thwart the libertarian wing of his Liberal Party was seen as a politically risky move that effectively rules out a marriage equality bill passing under his government. It comes just six months after he narrowly survived a party room coup and amid dismal polls that have reignited speculation over his future.

In the Australian parliament, crossing the floor is extremely rare and lawmakers can face severe retribution up to expulsion if they defy the party to vote against their colleagues. The coalition's current position is against same-sex marriage. Public opinion is strongly in favour of legalising the practice but Abbott, a socially conservative Catholic, has manoeuvred to head off a free vote before the next election. Abbott announced after the next election MPs and senators would be able to vote freely, raising the prospect of putting the question to the nation through a referendum or plebiscite.

"We decided to keep faith with the position we took to the last election - the position that we've had for quite some time - for this term of Parliament, but let's give the people their say in the next term of Parliament," Abbott told reporters following the near six-hour meeting.

"If the people want a change, fine. If the people decide to support the existing definition of marriage between a man and a woman, obviously I'd be pleased and I think everyone else should accept that," he added.

Abbott defended the tactics used to defeat the vote.

"Members opposite will want the politicians to decide, this government wants the people to decide," he told fellow politicians in parliament.

The tactical success over gay marriage could prove politically costly as Abbott struggles to keep his footing following a series of perceived gaffes and amid a sagging economy.