The Australian Green party is predicting that gay marriage will soon become law as a poll shows 57 per cent of the public are in favour of the change.

Of the 37 per cent who were against the change, 16 per cent were opposed and 21 per cent were strongly opposed.

The survey of 1,400 people was carried out by Nielsen and Fairfax newspapers. It follows a recent poll by gay rights groups which found that 62 per cent of the public want marriage equality.

Greens leader Bob Brown told reporters today that he believed the change would take place while Julia Gillard, who is opposed, remains prime minister.

“I confidently predict we will see an end to discrimination and the marriage laws during this period of government,” he said.

Greens Senator Sarah Hanson-Young said voters should tell their local MPs to get behind public opinion, ABC reports.

“Let Julia Gillard and Tony Abbott know that enough is enough,” she said. “It’s Julia Gillard and Tony Abbott, the leaders of our country, who are falling well behind.”

The Greens, who are a coalition partner in Ms Gillard’s minority Labor government, won a motion last week for Australian politicians to canvass voters on allowing gay marriage.