The extent of alleged paedophilia in Catholic institutions has been laid bare for the first time with a royal commission hearing that almost 4500 people have made claims of child sexual abuse over the past 35 years.

Data gathered by the Royal Commission into Institutional Responses to Child Sexual Abuse show certain Catholic orders had a high proportion of alleged abusers, including the Christian Brothers, the Marist Brothers and St John of God.

Francis Sullivan, chief executive of the Catholic Church's Truth, Justice and Healing Council, which assisted the royal commission's analysis of alleged abuse, became emotional as he addressed the packed public hearing before Justice Peter McClellan​.

"These numbers are shocking," he said. "They are tragic and they are indefensible. Each entry in this data ... represents a child who suffered at the hands of someone who should have cared for and protected them."