The rule was passed at a conference on Friday
Italy's bishops have adopted a policy, with backing from the Vatican, that states they are not obliged to inform police officers if they suspect a child has been molested.
The Italian Bishops' Conference said the guidelines published on Friday reflected suggestions from the Vatican's office that handles sex abuse investigations.
Victims have denounced how bishops systematically covered up abuse by moving priests while keeping prosecutors in the dark.
Only in 2010 did the Vatican instruct bishops to report abuse to police — but only where required by law.
Italian guidelines cite a 1985 treaty between the Vatican and Italy stipulating that clergy aren't obliged to tell magistrates about information obtained through their religious ministry. The guidelines remind bishops, however, they have a ''moral duty“ to contribute to the common good.
The ruling comes less than a week after Pope Francis appointed a former child victim as one of the first members of a new commission to help the Catholic Church put an end to clerical sexual abuse.
A UN report published in March blasted what it called the Vatican's code of silence" around abusive priests.
UN children's rights experts estimate "tens of thousands of children worldwide" have been sexually abused by predatory clerics as a result of moving, rather than reporting, paedophiles.
Speaking to Il Corriere della Sera, Pope Francis said at the time: "The Catholic Church is perhaps the only public institution to have acted with transparency and responsibility.
"No-one else has done more. Yet the Church is the only one to have been attacked."