The numbers will be vital, when the results of Australia's marriage equality vote come back.

It's a non-binding postal survey, so there's nothing compelling the government to change the law in the event of a 'yes' vote.

Australian religious leader Father Rod Bower told Mike Hosking a slim 'yes' majority will lend credibility to politicians looking to vote the other way.

''50.1% would be a win, but I think that would make it more politically difficult for the Prime Minister. He has a very difficult time with the extreme right of his party.''

LISTEN ABOVE AS FATHER ROD BOWER SPEAKS WITH MIKE HOSKING