UPDATE: THE "hero" spearheading the push for a royal commission into child sexual abuse in the Catholic Church has welcomed Opposition Leader Tony Abbott's support as a "magnificent gesture".

"My God, (Cardinal) George Pell's best mate!" Detective Chief Inspector Peter Fox said when told by news.com.au of Mr Abbott's support.



"Whether I'm an Abbott fan or not ... I really wasn't counting on his support but now that he's backing the royal commission that will probably change my mind about him a hell of a lot."

Det Chief Insp Fox's revelations about priest paedophiles and cover-ups have fuelled the push for a commission, with politicians from all parties - including former Labor PM Kevin Rudd and former Liberal PM Malcolm Fraser - supporting the idea.



Det Chief Insp Fox, a senior investigator who spent decades unearthing evidence of abuse, said he welcomed the support and felt that the movement was "on a real roll" but said he would not relax until it was in the bag.



"I’m never going to allow myself to relax until we have (a commission) for certain," he said.



"This isn't just now it's been going on ... people have been plotting this for 15 years. It's looking more promising now than at any time in the past but I won't take it for granted until it's stamped and done."



Mr Abbott today backed a Royal Commission into child sexual abuse as long as it was not limited to a single institution.



However, Mr Abbott made clear that support for an inquiry would only be given if it did not focus on just one organisation. He effectively said he would not back a royal commission which looked only at the Catholic Church.



He said in a statement that "if the government were to propose a royal commission to investigate the sexual abuse of children, it is something the Coalition would be prepared to support".



"Any investigation must be wide-ranging, must consider any evidence of the abuse of children in Australia, and should not be limited to the examination of any one institution," he said.



"It must include all organisations, government and non-government, where there is evidence of sexual abuse."



The Opposition Leader repeated his condemnation of child molestation and said the community must have "zero tolerance for the sexual abuse of children".



"Wherever abuse has occurred it must be tackled and it must be tackled vigorously, openly and transparently," he said.



"It’s clear that for a long period there was insufficient awareness and insufficient vigilance when it came to predatory behaviour by people in positions of authority over children.



"A lot of terrible things have been done, and a lot of people have suffered deeply."



He said that "victims must be allowed to heal, and perpetrators must be brought to justice".



There have been concerns within the Opposition that an inquiry would deal only with allegations against Catholic priests, who have been at the centre of recent claims of abuse.



"If there is to be a royal commission into paedophilia, it should be into all groups who have covered up, not just the Catholics," tweeted Liberal tourism spokesman Bob Baldwin today.



A national royal commission into all abuse allegations would take up a lot of time and money but the Government would be unlikely to call for an inquiry which could be interpreted as an attack on the Catholic Church.

Government Whip Joel Fitzgibbon today joined demands for a royal commission in the interests of "the victims, their families and the Catholic Church".



He wants a national inquiry but did follow Mr Abbott and say other organisations had to be scrutinised.



Mr Fitzgibbon, the MP for Hunter where recent claims of sexual abuse by Catholic priests have emerged, said there was a need for assurances that "no crimes or serious breaches of trust and responsibility have gone unpunished".



And he said this could only be achieved through an inquiry with the powers of a royal commission.



"Further, the Catholic Church will struggle to re-build its reputation while ever questions about institutional wrongs are not properly tested," he said in a statement.



"Worse, the Church will remain subject to all kinds of allegations and innuendo unless a formal process is established. And all the Church's on-going good work will pass unnoticed and unappreciated until the allegations are properly dealt with."



Mr Fitzgibbon said he had exchanged views today with Catholic Bishop of Maitland and Newcastle Bill Wright.

Prime Minister Julia Gillard is yet to make public comment on the possibility of a royal commission, after senior NSW police officer Peter Fox broke his silence over an alleged cover-up of a pedophile network inside the Catholic Church.

Det Chief Insp Fox, who has ignited calls for a Federal royal commission into child abuse in the Catholic Church, says police are trying to undermine his credibility.

He has tweeted:

"The police dirt campaign has already started against me circulating rumours I am (psychologically) unstable".

Det Chief Insp Fox, who investigated abuse by clergy for decades, revealed last week that "the church covers up, silences victims, hinders police investigations, alerts offenders, destroys evidence and moves priests to protect the good name of the church" and said that he was stood down from his investigation while he was compiling "explosive" evidence from a key witness.

His claims prompted NSW Premier Barry O'Farrell to start a special inquiry into child abuse, but Det Chief Insp Fox says he will not rest until there is a royal commission.

He also says there are more revelations to come:

"I've got much more on all of this. Watch this space".

While Archbishop of Sydney Cardinal George Pell says the church has already apologised and has questioned whether a commission would serve any purpose, politicians have joined victims' groups to call for a Federal commission.

Independent Senator Nick Xenophon told news.com.au it was about healing and closure for victims.

"The tipping point has been the very serious allegations by Peter Fox about the cover ups and destruction of evidence," he said.

"This could be a very powerful and useful exercise to clean the air and bring some closure.

"I think it's about how do we stop this from happening again. It should be about victims, how they get a fair go.

"If you look at the suicide rate for victims it is 17 times higher than the rest of the community. We have a duty of care."

The Gillard Government is now under pressure from its own back bench and influential independents to call a judicial inquiry into child abuse by priests.

Demands are mounting for a high-powered investigation with Liberal shadow minister Senator David Johnston today warning sex abuse claims were harming the reputation of the Catholic Church.

"This has been an absolute blot on the landscape in terms of people's faith and trust in the church," Senator Johnston said.

Labor's Nick Champion today called for a "broad inquiry that deals with the issue once and for all".

"We probably do need a royal commission," he said on Sky News.

Parliament's cross bench MPs and senators are close to uniting on the issue with Tony Windsor, Craig Thomson and Peter Slipper joining Senator Nick Xenophon in supporting government action.

Mr Windsor today was writing to the Prime Minister arguing that the "enormous number" of abuse victims felt "as though the system is letting them down".

"My advice to the prime minister and others ... is it is probably better to deal with this sooner rather than later," Mr Windsor told ABC radio.

Labor Senator Doug Cameron wanted the Catholic Church to be the only target of any inquiry.

Federal MPs have dismissed the response of NSW Liberal Premier Barry O'Farrell who has launched an inquiry into police handling of abuse claims against priests in the Hunter region.

Calling the inquiry "pathetic" and well short of a national investigation, Mr Windsor said: "It almost makes a mockery of the people who have suffered."

Do you have personal stories about child abuse in the church? Email tory.shepherd@news.com.au