Pope Francis has issued a new law requiring all Catholic priests and nuns to report sexual abuse and cover-ups by their superiors to church authorities.

The unprecedented move by the pontiff, which will apply to more than 1 million members of the clergy, promises protection for whistle-blowers and requires all dioceses around the world to have a system in place to handle claims confidentially.

Priests and nuns will now be required to inform church authorities whenever they learn or have "well-founded motives to believe" that a cleric or sister has engaged in child sex abuse, sexual misconduct with an adult, or possesses child pornography — or that a superior has covered up any of those crimes.

The rules also apply to historical cases meaning priests and nuns can retroactively report abuse.

It is thought that the Vatican is likely to see an avalanche of abuse and cover-up reports in the coming years, as a result.

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However, the law stops short of requiring them to report suspected abuse to the police.

The Vatican has long argued that doing so could endanger the church in places where Catholics are a persecuted minority.

In another legal first for the Vatican, the pope mandated that victims reporting abuse must be listened to and supported, as well as offered spiritual, medical and psychological assistance. It does not however, stipulate that they should receive financial reparations.

Pope Francis has promised a more robust response to the problem than his predecessors, calling for an “all out battle” against a crime that should be “erased from the face of the Earth”.

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In March, he signed a law that made it compulsory in law to report the sexual abuse of children within the Vatican and in its diplomatic missions.

He also promised "concrete action" would be taken against child sexual abuse by Catholic priests during an extraordinary summit of bishops in Rome in February.

But members of the clergy continue to speak out about the way claims of abuse have been handled.

Juan Carlos Cruz, a Chilean abuse survivor, said during the meeting in Rome that when he reported abuse to religious authorities he was treated as a liar and an enemy of the Church.

“You are the physicians of the soul and yet, with rare exceptions, you have been transformed – in some cases – into murderers of the soul, into murderers of the faith,” he said. “What a terrible contradiction.”

The Vatican was also rocked by the conviction earlier this year of Australian cardinal George Pell, who was found guilty of molesting two choirboys earlier this year.

In 2016, reports emerged that Australian police were investigating abuse allegations against Pell, then the third most powerful man in the Vatican, that involved minors.