Prime Minister Tony Abbott has said his position on gay marriage remains unchanged following its legalisation throughout the USA overnight.

The US Supreme Court ruled on Friday that marriage equality is a nationwide right and will now require all states to carry out and recognise same-sex marriage.

Mr Abbott, a long-time opponent of same-sex marriage, was asked about the issue this morning.

"What happens in the United States is obviously a matter for the United States, just as what happened in Ireland a few weeks ago is a matter for the Irish," he said.

"Obviously there is a community debate going on, I have views on this subject which are pretty well known and they haven't changed."

However, not all his government colleagues feel the same, with Education Minister Christopher Pyne suggesting the issue would probably return to Parliament after the winter break.

"When we come back in spring there's every possibility that will be back on the agenda," he said, adding that a vote should be held this year.

The Greens say the landmark ruling in the US is the loudest call yet for marriage equality in Australia.

"We clearly have some catching up to do here," Senator Janet Rice said in a statement.

"The Greens are committed to working with our cross-party colleagues to make sure this happens by the end of the year."

Former prime minister Kevin Rudd says now is the time to act on marriage equality in Australia.

"Fantastic decision in support of Marriage equality by US Supreme court," Mr Rudd said on Twitter on Saturday.

"Time now for Oz to act."