Pope Benedict has described the abuse as shameful and hateful
The Vatican is due to publish a letter from Pope Benedict XVI to Irish Catholics, asking forgiveness for paedophilic abuse by priests.
The pastoral letter is the first public statement by the Vatican on the sexual abuse of children dating back decades.
It follows revelations of paedophilia within the Irish Catholic Church, which have rocked the institution.
Scandals involving Catholic priests have been reported in other countries, including the Pope's native Germany.
The Vatican recently denounced attempts to link the Pope to a child sex scandal in Germany.
His former diocese has only said that he once unwittingly approved housing for a priest accused of child abuse.
In recent months paedophile scandals have also rocked the Church in the Netherlands, Austria and Switzerland.
The BBC's David Willey in Rome says that by implication, the measures decided by the Pope will have a much wider application than Ireland alone.
The Pope's letter will be published on the Vatican website at noon (1100 GMT) on Saturday.
It has also been sent to the bishops of Ireland so it can be read out at Masses across the country on Sunday.
The Pope has said he hopes it will "help in the process of repentance, healing and renewal".
The message is expected to express contrition for what he himself has already described as shameful and hateful behaviour by some priests.
It will include guidelines on preventing and punishing sexual abuse of children by priests.
Victims rights groups are demanding an assurance by the Pope that there will be no further cover ups by his bishops.
They also want a clear instruction that it is the responsibility of local church hierarchies to inform the police about cases of paedophilia by priests which come to their notice, as well as to report them back to Rome.
Last year a damning report into child abuse in the Dublin archdiocese criticised the Catholic Church hierarchy for covering up hundreds of cases going back to the early 1970s.
But what was first perceived in Rome as a series of local scandals has now escalated into a worldwide problem for the Catholic Church with new allegations emerging each week from Catholics claiming they have been victims of sexual abuse by priests.
The Catholic Church is on the defensive, its reputation as a guardian of morality at risk, our correspondent says.
And there is the prospect of an avalanche of claims for compensation by victims, which could lead to financial ruin in some dioceses, as has already happened in the US, where the greatest number of cases has been reported.