The Vatican has issued new rules on the handling of abuse cases amid a worldwide scandal, ordering quicker investigations of paedophile priests and extending the statute of limitations.

Announcing the measures in a bid to fend off accusations of high-level complacency, the Church also classified child pornography as a crime and made the abuse of mentally handicapped people a crime as serious as paedophilia.

The raft of new rules contains "more rapid procedures to deal with the most urgent and serious situations more effectively," the Vatican said in a statement.

But they notably do not deal with handing abusers over to civil criminal authorities, a key demand of advocacy groups.

Vatican spokesman Federico Lombardi explained in a note that the rules are part of Church law and thus "exclusively concern the Church (while) compliance with civil law" was already an instruction contained in guidelines published in April at the height of abuse scandals sweeping the Church.

Internal Church investigations will remain behind closed doors "in order to protect the dignity of everyone involved," Lombardi said.

The accelerated procedures provide for an "extra-judicial decree" or referring the most serious cases directly to the pope with a view to defrocking offending priests, Lombardi told a press briefing.

The new rules notably update a 2001 document -- signed by Pope Benedict XVI's predecessor John Paul II -- dealing with "serious crimes."

That text was prepared by Benedict, who as Cardinal Joseph Ratzinger was the Vatican's chief moral enforcer as head of the Congregation for the Doctrine of the Faith (CDF).

Paedophile priest scandals and allegations of high-level cover-ups have surged again since last year and rocked the Catholic Church in Europe and the United States.

The pope himself has faced allegations that, as archbishop of Munich and later as the head of the CDF, he helped to protect predator priests.

Benedict has accepted a number of resignations by bishops and other high-ranking clergy in recent months.

The head of the world's 1.1 billion Catholics issued a pastoral letter to Irish Catholics in March expressing shame and remorse for the revelations of abuse committed by those entrusted with the care of young people in Ireland, in many cases stretching back decades.

The scandals snowballed with revelations in the pope's native Germany, Belgium, Austria, United States, Brazil and other countries.

Benedict has repeatedly condemned paedophile priests, and he has met with abuse victims in Australia, the United States and Malta.

The CDF is preparing "further instructions for bishops so that the directives it issues on the subject of sexual abuse of minors, either by the clergy or in institutions connected with the Church, may be increasingly rigorous, coherent and effective," Lombardi said.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.