Pope Francis has vowed that the Catholic Church will “never again” cover up clergy sex abuse and demanded that priests who have raped and molested children turn themselves in.

Pope Francis dedicated his annual Christmas speech to the Vatican bureaucracy on Friday to abuse — evidence that a year of devastating revelations of sexual misconduct and cover-up has shaken his papacy and caused a crisis of confidence in the Catholic hierarchy.

Francis acknowledged that the church in the past had failed to treat the problem seriously, blaming leaders who out of inexperience or short-sightedness acted “irresponsibly” by refusing to believe victims.

But he vowed that going forward the church would never cover up or dismiss cases again.

“Let it be clear that before these abominations the Church will spare no effort to do all that is necessary to bring to justice whosoever has committed such crimes,” he said.

He urged victims to come forward, thanked the media for giving them a voice and issued a stark warning to abusers: “Convert and hand yourself over to human justice, and prepare for divine justice.”

Francis’ remarks capped a dreadful year for the Catholic Church — one that began with his own botched handling of a sprawling sex abuse scandal in Chile and ended with the US hierarchy in a free-fall of credibility as state prosecutors have begun uncovering decades of cover-up.

Francis has summoned church leaders from around the globe for a February abuse prevention summit, in an indication that he has come to realise that the problem is far greater and far more global than he had understood at the start of his papacy five years ago.

Francis warned the Vatican bureaucrats who run the 1.2 billion strong Church that the scandal now undermined the credibility of the entire enterprise and that from now on the church and all its pastors must embark on a continuous path of purification.

He prayed for help so that the Church can discern true cases from false ones, and accusations from slander.

“This is no easy task, since the guilty are capable of skilfully covering their tracks,” and choosing victims who they know will keep silent. He urged those who have been abused to speak out.

“The Church asks that people not be silent, but bring it objectively to light, since the greater scandal in this matter is that of cloaking the truth,” he said.

The cardinals and bishops of the Curia listened attentively, including the dean of the College of Cardinals, Cardinal Angelo Sodano, who has long been blamed for the Vatican’s refusal to acknowledge the depth of the problem during the quarter-century pontificate of St John Paul II.