Pope Francis has urged predator priests who have sexually abused children to turn themselves in, in one of his strongest comments ever on the crisis sweeping the Roman Catholic Church.

Key points: Pope Francis said the Catholic Church had made major errors in the past

Pope Francis said the Catholic Church had made major errors in the past He said the Church would "spare no effort" to bring abusers to justice

He said the Church would "spare no effort" to bring abusers to justice The comments come ahead of a February summit on the sexual abuse crisis

"To those who abuse minors I would say this: convert and hand yourself over to human justice, and prepare for divine justice," Francis said in his traditional Christmas address to the Curia, the Vatican's central administration.

While it was not immediately clear if the pope was referring to the Church judicial system, civil justice, or both, Vatican sources said they believed it was the first time the pope had made such a direct appeal.

Francis, who in the past has used the Christmas address to denounce cases of corruption and mismanagement in the Curia, this time concentrated on the global sexual abuse crisis rocking the Church.

"Let it be clear that, faced with these abominations, the Church will spare no effort to do all that is necessary to bring to justice whoever has committed such crimes," he said.

"The Church will never seek to hush-up or not take seriously any case."

He acknowledged that the Church had made serious errors in the past but promised to make "past mistakes opportunities for eliminating this scourge" from both the Church and society at large.

"It is undeniable that some in the past, out of irresponsibility, disbelief, lack of training, inexperience, or spiritual and human short-sightedness, treated many cases without the seriousness and promptness that was due," he said.

"That must never happen again. This is the choice and the decision of the whole Church."

The pope has summoned the heads of some 110 national Catholic bishops' conferences as well as dozens of experts and leaders of religious orders to the Vatican from February 21 to 24 for an extraordinary meeting on the sexual abuse crisis.

Victims of clerical sexual abuse are hoping that the meeting will finally produce a clear policy to make bishops accountable for the mishandling of abuse cases.

Reuters