Veteran broadcaster Alan Jones became an unlikely champion of gay rights on Wednesday when he delivered a moving speech in support of legalising same-sex marriage on his breakfast radio show.

What began as one of Jones' trademark attacks on Labor leader Bill Shorten, in which he called the Opposition Leader "bereft of ideas" and unelectable, metamorphosed into a heartfelt endorsement of Labor's intention to introduce a bill to Parliament to legalise same-sex marriage.

"I've said it before, I don't understand the complexity of it ... we're not telling anyone what to believe," Mr Jones said at the tail end of his 2GB breakfast program.

"It is 2015. On this issue we must respect the view of others.

"The reality is this: in a very difficult world, which is often impersonal, uncaring, ruthless and sometimes brutal in personal relationships, love can prove elusive.

"And my view is that when people find love they should be able to celebrate it. And they shouldn't be discriminated against according to the nature of that love," he said.

"To deny people the recognition for a relationship which is based on love is to deny in my opinion one of humankind's most basic, but as I said elusive, qualities."

The outspoken broadcaster ended with what seemed to be a call to Prime Minister Tony Abbott.

"Let the Parliament vote. It makes the laws of the land. It may well be that the nation doesn't need a referendum," Jones said, referring to Ireland's  'Yes' vote in its national referendum on same-sex marriage last week, "but we shouldn't be frightened about celebrating the love of one person for another."

Hours later, Mr Abbott hinted during Question Time that same-sex marriage should be brought before Parliament via a cross-party bill, in a major shift in his language on the reform.

Once the talkback lines opened, Jones' own sexuality was questioned by a Christian caller who went by the name Robyn.

"Are you a homosexual?" Robyn asked Jones.

"That's irrelevant to the issue," he responded.

"The issues is marriage definitionally, of course, is a union between man and a woman," he said.

"It's not what I think, you think, Bill Shorten thinks. It's what the community thinks, and the Parliament thinks, and let those people express their view."