Australian prime minister Julia Gillard has confirmed she will allow Labor MPs a free vote on gay marriage, but it is not believed the bill will succeed.

The premier wrote in The Age that the conscience vote would allow MPs to decide “according to their own values and beliefs” on an issue which has divided her party.

Ms Gillard is on the record as opposed to marriage equality and sources said this did not mean she has changed her view.

In the past, she has said Labor MPs will not be allowed a conscience vote on the issue if it is debated in parliament.

The party will debate the issue at its upcoming December conference.

Gillard wrote: “My position flows from my strong conviction that the institution of marriage has come to have a particular meaning and standing in our culture and nation and that should continue unchanged.”

Labor’s Queensland, Tasmania, West Australia, South Australia, Victoria, ACT and Northern Territory branches have all passed motions in support of marriage equality.

A recent poll has shown majority support among the electorate for the move to introduce gay marriage, with 80% of those aged 18-24 agreeing with the idea.

But commentators say any gay marriage bill would likely fail under such a free vote. Labor controls 72 of the 150 seats in the House of Representatives, with a further 72 organised as a four-party coalition.

The coalition parties are predicted to vote solidly against a gay marriage motion, and with Labor split on the issue, many believe a majority would be unattainable.