Archbishop Dermot Clifford has said he is profoundly sorry for the failings in Cloyne.
The senior cleric, appointed Apostolic Administrator in Cloyne since John Magee stood down as bishop, insisted all efforts were now being made to protect children.
The cleric named in 'chapter nine' of the Cloyne Report into the abuse, known as Fr Ronat, was suspended from all ministry in Cloyne in November 2005. He has not been allowed to minister to the public since.
"He was only allowed to celebrate Holy Mass in the privacy of his own home without a congregation," the Archbishop said.
"He was also instructed not to wear clerical dress or present himself as a priest. Priests are in a position of special trust and responsibility, particularly where young people are concerned. To betray that trust by engaging in the heinous crime of child sexual abuse is appalling."
The Archbishop said it was a huge regret the Catholic Church's own rules on reporting abuse allegations were not followed as recently as 2008.
"As a result, further hurt and distress was caused to complainants," he said. "They were also denied the justice they deserved."