SYDNEY (Reuters) - Australia should introduce a law forcing religious leaders to report child abuse, including Catholic priests told of abuse during confession, said a report on Friday which detailed institutional abuse, particularly in the Catholic Church.

One the country’s top catholics, Melbourne Archbishop Denis Hart, said such a law would undermine a central tenet of Catholicism, the confidentiality of the confessional, and warned that any priest breaking the seal of confession would be excommunicated.

The 17-volume document from the Royal Commission into Institutional Responses to Child Abuse marks the end of one of the world’s biggest inquiries into child abuse and leaves it to the government to decide whether to enact its recommendations.

The five-year investigation found “multiple and persistent failings of institutions to keep children safe, the cultures of secrecy and cover-up, and the devastating affects child sexual abuse can have on an individual’s life”, the commission said in a statement.

The report detailed tens of thousands of child victims, saying their abusers were “not a case of a few rotten apples”.

“We will never know the true number,” it read.

In a statement, the Vatican said the report “deserves to be studied seriously” but made no mention of its specific suggestions.

The volumes of the Final Report of the Royal Commission into Institutional Responses to Child Sexual Abuse sit on the table before the signing ceremony of the release of the papers at Government House in Canberra, Australia, December 15, 2017. Royal Commission into Institutional Responses to Child Sexual Abuse/Handout via REUTERS

“The Holy See remains committed to being close to the Catholic Church in Australia – lay faithful, religious, and clergy alike – as they listen to and accompany victims and survivors in an effort to bring about healing and justice,” the statement said.

The inquiry spanned religious, government, educational and professional organizations but heard many accounts alleging abuse cover-ups in the Australian Catholic Church, including allegations of moving priests suspected of abuse between parishes to avoid detection.

Of survivors who reported abuse in religious institutions, more than 60 percent cited the Catholic Church, which demonstrated “catastrophic failures of leadership”, particularly before the 1990s, the report said.

The Vatican statement said Pope Francis had made clear that “the Church is called to be a place of compassion, especially for those who have suffered, and reaffirmed that the Church is committed to safe environments for the protection of all children and vulnerable adults.”

The Royal Commission report said clergy told of child abuse in the confessional should be required by law to report it and called for the Catholic Church to make celibacy voluntary for clergy, adding that it contributed to child abuse.

“I would feel terribly conflicted, and I would try even harder to get that person outside confessional, but I cannot break the seal,” Hart told reporters.

“The penalty for any priest breaking the seal is excommunication, being cast out of the church, so it’s a real, serious, spiritual matter, and I want to observe the law of the land ... but as part of my identity as a priest, I have to observe the seal of the confession.”

A similar recommendation was made during Ireland’s 2009 child abuse inquiry, leading to a mandatory reporting law in 2015. Some U.S. states have similar requirements.

The Australian report also called for a National Office for Child Safety and national child safety standards, child abuse reporting and record keeping, which would cover all institutions engaged in child-related work.

Australian Prime Minister Malcolm Turnbull said the inquiry had “exposed a national tragedy” and that the government would consider the recommendations and respond in full next year.

Sydney Archbishop Anthony Fisher, said in a statement that he was “appalled by the sinful and criminal activity of some clergy, religious and lay church-workers (and) ashamed of the failure to respond by some church leaders”.

The inquiry heard previously that the Australian Catholic Church had paid A$276 million ($212 million) in compensation to thousands of child abuse victims since 1980.

($1 = 1.3040 Australian dollars)