Prime Minster Tony Abbott’s sister has called for a conscience vote on same-sex marriage following Ireland’s historic referendum voting in favour of it on Saturday.

Christine Forster, a Sydney City councillor who is also gay, said Australia needed to move forward on a free vote.

• Gay marriage referendum push
• Ireland votes ‘Yes’ to same-sex marriage
• Lambie’s gay marriage warning

“His (Mr Abbott’s) personal position is well known,” Ms Forster told Sky News on Sunday night.

“I would like nothing more than for the current Prime Minister – who happens to be my brother – to take the same position David Cameron took.

“We need to move forward on a free vote.”

Ms Forster said amending the Marriage Act was “simple”, changing the definition of a marriage “between a man and a woman”, to “two consenting adults”.

Christine Forster said Australia needed to move forward on gay marriage. Photo: Twitter

“This can be changed in the parliament,” she said.

“Even if it didn’t get up the first time, it would be a pretty close result, and we would not be far away from getting this through.”

Some MPs, including from the Prime Minister’s own back bench, are pushing for a referendum after Ireland voted overwhelmingly in favour of allowing same-sex marriage in the referendum.

But Mr Abbott on Sunday expressed a different view to his sibling, saying gay marriage in Australia was a matter for the Federal Parliament, rather than a popular vote.

Mr Abbott feels it is a matter for the Coalition partyroom to decide whether MPs get a conscience vote, should legislation come before parliament.

“It’s up to members of parliament who are eager for change to decide whether they want to bring it forward,” he said.

But Independent Senator for Tasmania Jacqui Lambie backed a referendum over a conscience vote on gay marriage.

Ms Lambie, though, does not support the concept of same-sex couples exchanging vows.

“We have an elderly population here in Australia … I don’t think you are going to get the same result that has just happened in Ireland,” she told Sky News.

The Church’s reaction

Meanwhile, the once-dominant Catholic Church in Ireland is trying to come to terms with an overwhelming vote in favour of gay marriage.

“The Church has to find a new language which will be understood and heard by people,” Archbishop of Dublin Diarmuid Martin told reporters after mass at the city’s St Mary’s Pro-Cathedral.

“We have to see how is it that the Church’s teaching on marriage and family is not being received even within its own flock.”

The majority of Irish people still identify themselves as Catholic but the church’s influence has waned amid growing secularisation and after a wave of child sex abuse scandals.

During the campaign, bishops spoke against changing the law, while older and rural voters were thought to have accounted for much of the “no” vote.

– with AAP