The world's cardinals have prayed for guidance at unprecedented talks on paedophile clergy.

Around 150 of the Roman Catholic Church's 203 cardinals took part in the Vatican meeting organised by Pope Benedict XVI, where they also debated the issue of religious freedom and conversions of Anglicans to Catholicism.

The closed-door meeting was referred to by the Vatican as "a day of prayer and reflection" on the challenges facing the Church.

The issue of abuses by priests and cover-ups by bishops has exposed a raw nerve among many ordinary Catholics who are dissatisfied with the Vatican's handling of the issue and has put Church authorities on the defensive.

"I'm tired of talking about this topic. I've had it up to here," Mexican cardinal Javier Lozano Barragan told reporters on the sidelines of the talks.

"It's a real media storm," he said.

The publication in Ireland last year of a shocking report that documented hundreds of cases of child abuse by priests and systematic cover-up efforts by senior clergy has plunged the Church into its worst crisis in many years.

There have since been hundreds more revelations across the US and Europe.

"If the pope and cardinals want to make a difference, they would be meeting with law enforcement professionals, not with one another," said Joelle Casteix, 40, an abuse victim who travelled to Rome from the United States to protest.

"Experience tells us the Church will probably hear about our campaign today but won't do anything unless they're held up at legal gunpoint," Casteix, a member of the US anti-abuse campaign group SNAP, told reporters in Rome.

Lucy Duckworth, 28, who said she was abused by two priests when she was a child, added: "The church says they offer support to victims. I've had no such support. No phone calls from the Church. I pay for my own therapy."

The Survivors' Network of those Abused by Priests (SNAP) held a small protest in Piazza Navona in central Rome, in which abuse victims held up pictures of themselves as children when they were abused and handed out flyers.

Benedict has condemned the crimes with growing intensity, has met with victims and has tightened Church rules for dealing with abusers.

- AFP