The Greens demanded a royal commission after independent MP Tony Windsor said he would write to the Prime Minister to discuss an inquiry.
Former Labor MP Craig Thomson, who now sits as an independent, said he would back any inquiry, while former Liberal turned independent Peter Slipper said the issue was "clearly a matter of concern".
Independent South Australian senator Nick Xenophon said he would move a private member's bill for a royal commission if the government failed to act on the issue in a timely matter.
The calls for an inquiry follow a series of international scandals involving sexual misconduct by priests.
In March 2010, Pope Benedict apologised for the abuse of children by Irish priests following revelations sparked by a series of government-commissioned inquiries.
On Friday, NSW Premier Barry O'Farrell announced an inquiry into alleged child sex abuse at the hands of Catholic priests in the Hunter Valley, where hundreds of victims are believed to have been abused and 11 priests have been convicted since 1995.
A separate public inquiry in Victoria is investigating allegations of systemic child abuse, including that a number of Catholic priests might have been involved in the unreported deaths of two boys.
But Australia's most powerful Catholic, Archbishop of Sydney George Pell, yesterday questioned whether a royal commission into sex abuse inside the church would serve any purpose.
He was backed by Brisbane Archbishop Mark Coleridge and the Archbishop of Adelaide, Philip Wilson.
Cardinal Pell used the opening remarks of his sermon at Sydney's St Mary's Cathedral to re-characterise the growing chorus for a federal inquiry as a "disproportionate" attack on the church.
"We have to answer up for what we've done but any suggestion that we are the only culprit or only community producing culprits is entirely misleading," he said.
Cardinal Pell told The Weekend Australian on Friday that he accepted children were abused by priests, and that this was then covered up by other clergy, but these crimes were largely historic and not part of a systemic failing within the church.
But the former bishop of Toowoomba, Bill Morris - a one-time co-chairman of the nationwide body that sets Catholic policy in handling abuse allegations - said a royal commission was needed, although it should cover all institutions that have a duty of care over children.
Bishop Morris - sacked by the Vatican last year on doctrinal grounds, months after he set a precedent by forcing the church to accept legal liability for a teacher's abuse at a diocese school - said the "air needs to be cleared".
"All organisations who have dealt with children have to have questions asked of them and need to be looked at in the context of a royal commission so that this issue can finally be addressed," he said.
Bishop Morris said the Catholic Church had "gone a long way" in handling the problem and, although mistakes continued to be made in policing abuse and dealing with victims, he did not believe there was any culture of systemic cover-up in Australia.
Archbishop Coleridge did not support a royal commission, although he conceded the church could have handled abuse better.
Greens leader Christine Milne said yesterday that "with unprecedented claims by senior police that evidence is being destroyed or suppressed within the church, and that inquiries are being hampered, a national royal commission is needed to address what Cardinal Pell has described as a cancer.
"Whereas the criminal justice system investigates individual complaints, the coercive powers of a national royal commission are needed to examine the systemic failings that have allowed the church to cover up and hide this abuse over decades by moving the problem state to state," she said.
Senator Milne, a self-described extremely lapsed Catholic, questioned how senior clergy had been able to transfer priests and brothers to other schools - often interstate - rather than report alleged abuse to the police.
"The culture in families where the word of a child is not believed against that of a religious figure or where the church puts pressure on families not to go to the police has allowed the abuse to continue," she said. "It has resulted in family estrangement and agony for victims over decades. The victims of abuse need this royal commission."
Mr Windsor said at the weekend he would discuss a royal commission with Ms Gillard.
West Australian Labor MP Melissa Parke said she was "very concerned and would support a royal commission".
Labor senator Doug Cameron said he was extremely concerned about the depth and breadth of the allegations of child sex abuse and "now is the time for a royal commission. No other organisation in the country could have resisted a national inquiry for this long".
Northern Territory Labor senator Trish Crossin told The Australian that the need for a broader inquiry into the issue - including a possible royal commission - was worth raising in Labor caucus. She said there were alternatives to a royal commission, although she did not think a parliamentary inquiry was adequate.
The Prime Minister said in Bali on Friday that she was "very concerned . . . about the distressing human stories that we continue to hear - what happened to people, and what happened to people over a long period of time".
She said she would review the reports when she returned to Australia. Yesterday her office declined to comment further.