The ongoing debate over same-sex marriage is set to intensify when Parliament resumes, after it emerged that a cross-party bill will be introduced on August 11.

The bill will be backed by two Liberal co-sponsors, Warren Entsch and Teresa Gambaro, and two Independents, Andrew Wilkie and Cath McGowan.

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A further two Labor MPs, Terri Butler and Laurie Ferguson have co-sponsored the bill.

The issue could divide the party room, particularly because it will enter parliament before a conscience vote is held. The Coalition have previously refused to hold a conscience vote.

Parliament broke up last week for the winter break.

The news was welcomed by Australian Marriage Equality national director Rodney Croome.

“Because this bill will be signed by two Liberals, it will have the best chance of achieving a Coalition free vote, and because it has cross-party support, it has the best chance of passing.

“With momentum growing after marriage equality in Ireland and the US, this bill gives Australia the strongest opportunity we have ever had of achieving marriage equality.

“We aim to win majority support in parliament with grassroots mobilisation, rallies and advertising campaigns throughout July and across the nation.”

Croome hopes the Coalition allow a free vote on the co-sponsored bill.

“It is untenable for Coalition MPs to introduce legislation they can’t vote on,” he added.

A key proponent of marriage equality, Labor MP Stephen Jones told AAP he was pleased with the support of Coalition MPs.

“The question is whether [Prime Minister] Mr Abbott will support a conscience vote – unless he does, it is all academic.”

Not all the reactions were positive, with Lyle Shelton – managing director of the Australian Christian Lobby – taking to Twitter afterwards.

A bill to abolish husband & wife in the Marriage Act will be introduced to Parlt on Aug 11. Time to let MPs know kids need their mum & dad.

— Lyle Shelton (@LyleShelton) July 1, 2015

Gay marriage was declared legal across all of the United States last week, sparking scenes of celebration across the country.

Ireland voted for gay marriage in May, becoming the first country to do so by popular vote.