The Catholic Church in Ireland covered up widespread allegations of sexual abuse of children by priests for four decades, a damning official report released on Thursday said.

Four archbishops routinely protected abusers and failed to enforce the law, the three-year investigation into the Dublin Archdiocese, the country's largest, found.

"The Dublin Archdiocese's pre-occupations in dealing with cases of child sexual abuse, at least until the mid-1990s, were the maintenance of secrecy, the avoidance of scandal, the protection of the reputation of the Church, and the preservation of its assets," the report said.

It added: "All other considerations, including the welfare of children and justice for victims, were subordinated to these priorities."

Irish Justice Minister Dermot Ahern, presenting the report in Dublin, said it "catalogues evil after evil committed in the name of what was perversely seen as the greater good."

He added: "There is no escaping the cruel irony that the church, partly motivated by a desire to avoid scandal, in fact created a scandal on an astonishing scale.

"In many many cases the welfare of children counted for nothing and the abusers were left free to abuse, to visit evil on the innocent."