KEVIN Rudd has changed his mind on same sex marriage and now believes the federal parliament should legalise it.
But he says any legal recognition for gay marriage should make religious institutions exempt from having to change their own practices.
Last September Mr Rudd was one of 98 MPs to vote against a marriage equality bill.
"This change in position has come about as a result of a lot of reflection, over a long period of time," he wrote in a blog post on Monday announcing his change of mind.
"I have long resisted going with the growing tide of public opinion just for the sake of it."
He recounted a recent conversation with a gay, "God-botherer" former political staffer who told Mr Rudd he hoped to get married to another man one day.