Australia's shadow treasurer Chris Bowen announced his support for marriage equality on Sky's Australian Agenda on Sunday morning.
"In a conscience vote I have decided I would support same-sex marriage and that's not traditionally the approach I took last time," he told Australian Agenda.
Bowen, a member of the party's right faction, has previously voted against marriage equality. He said in 2012 he would vote against it as many in his Western Sydney electorate had indicated their support for the current definition of marriage.
However, Bowen's change of heart adds another pro-marriage equality voice to the senior ranks of Labor.
"On my marriage certificate at home it has the Australian coat of arms, as it has on all of ours. It is our right as a citizen to get married, it should be a right applied equally."
"I know I have friends who have had to go overseas to get married. I don't think they should have to go overseas to get married as Australian citizens. So I would support it."
However, Bowen made it clear that he does not support deputy opposition leader Tanya Plibersek's recent push for Labor to bind on the issue.
Plibersek announced she would push for a binding vote at Labor's national conference in July. However, her plan was rebuffed by opposition leader Bill Shorten and other senior Labor figures.
"I think people should be given their own time to develop their thinking and their approach," Bowen told Australian Agenda.
"I also think that it is most likely to occur when the Liberal Party adopts a conscience vote and I think the chances of that are enhanced by Labor having a conscience vote."
Shadow minister for families Jenny Macklin told ABC's Insiders that she supported Plibersek's push.
"We in the Labor Party have very strong views about discrimination. We have taken those views forward over many, many years," she said.
"I don't think Australians believe in inequality on the basis of race or gender and I don't think we should do so on the basis of sexual preference. That's the principle. That's why I think it should be a binding issue."