A letter to Ireland's Roman Catholic bishops has been revealed by the broadcaster RTE that contradicts the Vatican's frequent claim it has never instructed clergy to withhold evidence or suspicion of child abuse from police.
The 1997 letter documents rejection of a 1996 Irish church initiative to help police identify paedophile priests.
Signed by the late Archbishop Luciano Storero, Pope John Paul II's envoy to Ireland, it instructs bishops that their new policy of making the reporting of suspected crimes mandatory "gives rise to serious reservations of both a moral and canonical nature".
Storero wrote that canon law, whereby allegations and punishments are handled within the church, "must be meticulously followed"; any bishop who tried to go outside canon law would face the "highly embarrassing" position of being overturned on appeal in Rome.
Catholic officials in Ireland and the Vatican declined requests to comment on the letter, marked "strictly confidential"; RTE said it had been given it by an Irish bishop.
To this day, the Vatican has not endorsed any of the Irish church's three documents since 1996 on safeguarding children. Irish taxpayers, rather than the church, have paid most of the €1.5bn to more than 14,000 abuse claimants dating back to the 1940s.
In a 2010 letter to Ireland condemning paedophiles in the ranks, Pope Benedict XVI faulted bishops for not following canon law and offered no explicit endorsement of child-protection efforts by the Irish church or state.
He was widely criticised in Ireland.