A yes vote on marriage equality is no guarantee of a law change in Australia.

It's been a sleepless night for "yes" supporters, even with the polls in their favour.

Australia correspondent Murray Olds said the Prime Minister hopes to get a law change in by Christmas in the event of a yes vote.

But he told Mike Hosking there are still hurdles to cross after the results come back.

''There is a small rump of conservatives in the coalition party room, and they don't want a bar of it. They want to delay, they want more protections.''

LISTEN ABOVE AS MURRAY OLDS SPEAKS WITH MIKE HOSKING