Twin bills to include same-sex couples in the legal definition of marriage were introduced into parliament on Monday.
One of the primate members bills was moved by Labor backbencher Stephen Jones, who foreshadowed the move at last year’s Labor Party National Conference.
The other was moved jointly by Independent MP Andrew Wilkie and Greens MP Adam Bandt.
Both bills contain clauses allowing ministers of religion to refuse marrying same-sex couples if they do not wish to.
Another similar bill put forward by Sarah Hanson-Young several months ago remains under consideration by the Senate.
While at this stage none of the three bills have the numbers to pass through parliament, they will not be voted on until May, so time remains for both sides to negotiate.
Mr Bandt is optimistic about the future of marriage equality in Australia.
He said that he expects gay marriage to be legalised by as early as the end of this year.
“I believe it is love that has brought us to this place in this debate and it is love that will carry us over the threshold of discrimination to full marriage equality,” he said.
But Liberal backbencher Barry Haase said the bills were an “affront to good government”.
“It doesn't make sense for good, honest, upright members of this chamber to be dragged into such a debate simply because the government of the day wishes to embrace the minorities,” he said.
"It is an attack on the rights of all those people who support marriage, and they are, I believe, the majority."
The latest Galaxy poll however, shows around 62% of those surveyed support gay marriage.
Mr Haase also said that gay couples should use the relationship registers provided by state governments instead.
On Tuesday, well-known comic actress Magda Szubanski came out publicly on Valentine’s Day as both gay and as a strong supporter of gay marriage.
In a statement to the press, she refuted Mr Haase’s assertion that relationship registers were enough for gay couples.
“The law means that you could be a serial killer and have killed all of your spouses and yet you would still be considered fit to marry, but if you are gay, then you are not worthy of these same rights,” she said.