The worst of the Catholic sexual abuse scandal may be over in Australia, but the crisis is likely to hit the church in Asia, Africa and parts of Europe within a decade, a report has warned.

The RMIT study, Child Sexual Abuse in the Catholic Church, has for the first time compiled the findings of 26 royal commissions, police investigations, judicial probes, government inquiries, church studies, and academic research from around the world since 1985.

It warns the gravest potential for future abuse of children and teenagers lies in the estimated 9,600 orphanages the church still runs, including 2,600 in India and 1,600 in Italy.

"[Child sexual abuse] has peaked and there has been a decline since the late 70s and early 80s and that's because it's been brought into the public arena," the study's co-author, Professor Des Cahill, said.

"But I think in the developing countries and in some of the European countries, there hasn't been a precipitating event to raise the issue into the public arena and I'm thinking particularly of countries in Asia and Africa.

The extent of church sexual abuse in the developing world is yet to be uncovered. ( Getty Images: Pascal Deloche )

"It may reassert itself, after this has all blown over, and come back in 30, 40 years' time … if the underlying issues are not addressed.

"I as yet have not seen any sign at the Vatican level, and even here in Australia, for the bishops to answer why did this happen and why did they — the bishops — react so poorly."

Examining reports from Australia, Ireland, the United States, Britain, Canada and the Netherlands, Professor Cahill and his co-author, theologian Peter Wilkinson, found that one in 15 priests, or about 7 per cent, allegedly abused children and teenagers between about 1950 and 2000.

They say even today children "are at risk in education and welfare institutions when they can be accessed by psychosexually immature and/or sexually deprived celibates, including priests and religious brothers".

However, Professor Cahill, who was an adviser to the Royal Commission into Institutional Child Sexual Abuse, believes the risks to children in Australian Catholic schools are now very low, mainly because of greater vigilance by parents, teachers and school authorities.

He says most Catholic school principals are married men and women, and are extremely conscious of the risks to children.

Australia's reliance on overseas trained clergy may pose safety risks for parishes. ( Getty Images: Godong )

The decision of the Catholic Church in Australia, the US, Britain, New Zealand and Canada to phase out large orphanages and move children into foster care has also substantially reduced the risk of abuse.

But controversially the report warns that Australia's reliance on overseas trained clergy — up to 40 per cent in some diocese — could be risky, as overseas bishops may try to banish offending or suspect priests to foreign postings.

"Is the phenomenon of child sexual abuse by priests and religious [brothers] likely to reappear and increase in the short or long term?" the report asks.

"The answer is unclear … It might happen, despite even the most stringent checks that an offending priest or religious might be recycled to Australia. In the US, not a few overseas priests, especially from the Philippines and India, have been charged and convicted."

The shortage of local candidates for the priesthood in many Western countries has, in the past, also led bishops to ordain men despite warnings from the heads of seminaries and training colleges that they were unsuitable.

These included "psychosexually immature, psychosexually maldeveloped and sexually deprived and deeply frustrated male priests and religious, particularly those who had not satisfactorily resolved their own sexual identity".

Professor Cahill and Dr Wilkinson do not blame the abuse crisis entirely on celibacy, but their report notes the low levels of abuse in the eastern rite Catholic churches — particularly the Maronite, Ukrainian, Melkite and Chaldean churches — where priests are allowed to marry and become fathers.

Professor Cahill is himself a former Catholic priest who resigned to marry and start a 40-year academic career.

He rejects the claim, often made by church conservatives, that the liberal reforms of the Second Vatican Council in the early 1960s loosened the morals of priests.

"Much of the abuse happened before Vatican II, during the 1950s and into the 60s," he said.

"And the majority of offending priests were either ordained before Vatican II or well progressed in their studies. I think we need to be suspicious of those explanations."