An Australian inquiry has accused the Catholic Church of having "seriously failed" to protect children from sexual abuse.

A five-year investigation into sexual abuse in Australia concluded that there were "catastrophic failures" by Catholic Church officials to address the allegations and concerns of victims.

"Tens of thousands of children have been sexually abused in many Australian institutions. We will never know the true number," a report by the Royal Commission into Institutional Responses to Child Sex Abuse has found.

"It is not a case of a few 'rotten apples.' Society's major institutions have seriously failed," the report, released on Friday (15 December), concluded.

More than 15,000 people contacted the commission to share their experiences of abuse. The commissioner has passed 2,500 cases on to the police for further investigation.

7% of priests who worked in Australia between 1950 and 2009 have been accused of child sex abuse, according to the report.

Prime Minister Malcolm Turnbull said the commission's findings exposed a "national tragedy." Australia's main Archbishop, Denis Hart, apologised for the Church's "shameful past" and said the report "will be taken very seriously."

The report includes 400 recommendations, including the suggestion that the Catholic Church overhaul its celibacy rule. It said that while celibacy was "not a direct cause of child sexual abuse", it had "contributed to the occurrence of child sexual abuse, especially when combined with other risk factors."

Hart said it was up to the Vatican to decide on the issue of celibacy. "It's a discipline which the church can change," he told Fairfax media.

The damning report comes several months after Australia's highest-ranking Catholic, Cardinal George Pell, was charged with "historic sexual abuse offences."

Cardinal Pell was one of Pope Francis' closest allies and the pontiff is facing mounting pressure to publicly condemn clergy abuse.

When he was appointed pope, Francis promised a "zero-tolerance" approach to sexual abuse within the clergy, but survivors say the Vatican has not shown a real commitment to holding abusers accountable.

Michael Rezendes, one of the Spotlight journalists who uncovered widespread sex abuse in the Catholic Church, told IBTimes UK: "Pope Francis does seem to have a tin ear for [the] issue [of sex abuse. He has promised a zero tolerance policy, but surrounded himself with people caught up in the scandal."

He set up a commission to investigate the issue and come up with recommendations. The pope appointed two survivors of clergy abuse to the commission. One of them, Peter Saunders, was sacked earlier this year, while the other, Marie Collins, resigned several months later out of frustration at the lack of progress and commitment to bring about change.

"[The commission] has yet to do anything significant at all," Rezendes said. "There are tens of thousands of victims around the world who are pretty frustrated by this."

IBTPOTY2017 Pictures of the week
Cardinal Pell faces Victorian parliament today.
One of Pope Francis' closest allies and Australia's top Catholic official, Cardinal Pell, has been charged with "historic sexual abuse offences."