A total of 272 allegations of child abuse were made against Catholic priests last year and twelve suspects are still in ministry.
A damning report into the extent of complaints found that initially only 53 accusations were reported to the watchdog, the National Board for the Safeguarding of Children in the Catholic Church.
However, after diocesan leaders were contacted to verify figures for the annual report, the number of allegations jumped five-fold.
It is understood the vast majority of complaints are historic and a very low number relate to allegations in the last year.
The National Board said the breakdown of allegations included 166 against religious orders and 106 made to dioceses.
There were 86 against deceased clerics or members of religious orders. Twelve suspects are still in ministry, the report stated.
The board also said that 174 allegations referred to clerics who had been or were removed from ministry, retired or have left the church after laicisation.
One In Four, the leading support group for abuse victims, said the report yet again showed the Catholic Church in Ireland is failing to fully commit to transparent child protection.
Executive director Maeve Lewis said dioceses and congregations have tried to hide behind data protection concerns to avoid taking part in a long-promised review of safeguarding practices.
Reviews have been possible in only three of the 26 dioceses and no congregation has been reviewed, One In Four said.
Ms Lewis said: "Despite promises of transparency and co-operation with the civil authorities, we still do not know to what extent the Catholic Church is complying with its own guidelines, or whether there is consistency in child protection practices across the country.
"The Church has consistently failed to reveal the full story of child sexual abuse until it is forced to do so."
Ms Lewis said authorities should consider expanding the Murphy Commission, which exposed shocking abuse in the Dublin Archdiocese and has also examined Cloyne Diocese in Cork.
"Ian Elliot (chief executive of the board) and his team are to be commended on their work in policy and training but they are clearly being impeded by forces within the Church in their monitoring role," she said.
"This must be frustrating in the extreme, and may also endanger children."