Independent MP Andrew Wilkie has called on the Prime Minister to allow a conscience vote on gay marriage, with an opinion poll today showing four out of five Australians support the move.

The Greens have introduced into the Senate a bill which would allow gay and lesbian couples to be married.

But Prime Minister Julia Gillard and Opposition Leader Tony Abbott both oppose any changes to the Marriage Act, a position they both reiterated during the recent election campaign.

Australian Marriage Equality has today released the results of a Galaxy Poll which shows 62 per cent of those polled support gay marriage, with the figure rising to 80 per cent among those between the ages of 18 to 24.

Seventy-eight per cent of those polled also want the Government to allow a conscience vote on the issue.

Australian Marriage Equality spokesman Alex Greenwich says the poll will put more pressure on the Government over the issue.

"This Parliament has an opportunity to make history and send the message that all love is equal or they can continue to entrench discrimination," he said.

Mr Wilkie says while there has been reform in recent years, Ms Gillard must allow a conscience vote.

"We still have this extra situation where the Marriage Act prohibits marriage by same sex couples. That is nothing short of legislated discrimination," he said.

"Why on earth won't the Prime Minister agree to a conscience vote?

"We know 62 per cent of Australians support same sex marriage, we know now that 78 per cent of Australians support a conscience vote in the parliament on same sex marriage.

"I think it's virtually unexplainable how the Prime Minister can be so prepared so consistently to be out of step with the will of the people."

The issue of gay marriage was a hot topic during the election campaign and Ms Gillard was confronted about the issue during a televised public forum in Sydney.