Macklin backs binding caucus vote on gay marriage

Labor frontbencher Jenny Macklin agrees the party's platform should change to bind MPs in support of same-sex marriage.

File image of plastic figurines depicting a female couple and a male couple

Senior Labor MP Jenny Macklin has backed a push for a binding vote on same-sex marriage, putting her at odds with Opposition Leader Bill Shorten.

Deputy Labor leader Tanya Plibersek wants the party to change its position of having a conscience vote on the matter but Mr Shorten says people should be convinced, not forced on the issue.

Ms Macklin says it's good the party is debating the issue ahead of Labor's national conference in July.

Shadow Treasurer Chris Bowen says he's changed his view on same-sex marriage and now supports a conscience vote on the issue.

But like Mr Shorten, he doesn't support a binding vote that is being pursued by Ms Plibersek.

"It's right for Tanya to put her point of view forward ... but it wouldn't be the approach I would support," Mr Bowen told Sky News.