Bill Shorten has reiterated his support for a free vote on marriage equality for Labor, rejecting calls for a binding vote from some in his party.
In an op-ed for Fairfax Media, Shorten wrote that he supports a free vote due to his respect for different views within the party.
"Solidarity still has powerful meaning in our party and a binding vote would put a handful of Labor MPs in a very difficult position," he said.
"Either they vote against their conscience, or they vote against the party they've dedicated their working life to serving."
Shorten also said that a binding vote in the Labor party would make it more difficult to persuade the Coalition to adopt a free vote.
"Not only is it far more difficult for us to call on Tony Abbott to give his party room a free vote if we bind ourselves, there is also the risk that the Coalition re-commits to binding against marriage equality," Shorten said.
"I'm hopeful Tony Abbott will allow his MPs a free vote when Parliament returns, to achieve this outcome."
There has been much discussion about marriage equality in the lead up to Labor's national conference this weekend, with various prominent MPs expressing their support for a binding vote.
Deputy opposition leader Tanya Plibersek argued in April that Labor ought to adopt a binding vote on the issue, telling Fairfax Media it was not a matter of life and death and therefore a conscience vote shouldn't apply.
"It is a clear question. Do we support legal discrimination against one group in this country? Or do we not?" she said.
Leader of the opposition in the senate Penny Wong has also spoken out in favour of a binding vote.
"There are many people who are well on the record as saying we should have a binding vote when it comes to matters of discrimination. I'm one of them," Wong told ABC Radio National earlier this month.
Recently, NSW Labor leader Luke Foley said he didn't want a binding vote, whereas ACT Chief Minister Andrew Barr said the party should bind on the issue.