Only five of Tony Abbott's Coalition MPs turned up to see Bill Shorten introduce a bill to legalise same-sex marriage in Australia

The Australian PM argued that the government is focussed on ‘urgent budget measures’

Bill Shorten introduces the marriage equality bill to near-empty government benches (YouTube )

Australia’s leader of the opposition Bill Shorten introduced a bill to legalise same-sex marriage on Monday, backed by members of his Labour Party and spurred on by Ireland’s landmark “yes” vote last month.

But when shorten delivered his speech on the need for marriage equality, telling parliament that “it is time,” he was speaking to a near-empty chamber: only five of Prime Minister Tony Abbott’s coalition MPs had turned up to see the bill introduced.

“The laws of our nation should give us hope. Our laws should tell our children what we believe. Our laws should tell strangers who Australians are,” he said, facing the bare government benches.

Gay rights activists fear that government MPs will be reluctant to back the bill when it is eventually voted on, as it could be seen as a political victory for the Labour leader over Mr Abbott.

Mr Abbott, a socially conservative Catholic and staunch opponent of marriage equality, was on Monday promoting the budget while the bill was being introduced.

At a Harvey Norman shop, Mr Abbott told reporters: “I accept that same-sex marriage is a significant issue.

“But frankly, this government’s absolute fundamental priority… is to get the most urgent budget measures through and by far the most urgent budget measure is the small business budget boost,” he said.

Pressure is mounting on Mr Abbott from his party’s libertarian wing and from within his own family to address marriage equality, while a survey conducted in Australia a year ago found that 72 per cent of people supported same-sex marriage.

The prime minister’s sister Christine Forster is engaged to a woman, and told the Australian Broadcasting Corporation: “It doesn’t change the institution of marriage at all, the institution of marriage still remains being about two people committing to each other, hopefully for life, and that being legally recognised by our government.”

Additional reporting by Reuters and PA