Respect gay marriage decision: Cormann

Finance Minister Mathias Cormann says he will vote against his personal views if a plebiscite on gay marriage shows Australians want change.

A senior Turnbull government minister who personally opposes same-sex marriage says he will abide by a national vote on the issue.

Mathias Cormann also expects his coalition colleagues to do the same, a position at odds with some of his fellow conservatives who say they will not be bound by the result.

"The reason you give the vote to the Australian people is because you obviously would respect the judgment the Australian people make," he told ABC radio on Tuesday.