SYDNEY, Australia — A royal commission investigating the sexual abuse of children in Australia found Friday that the nation was gripped by an epidemic dating back decades, with tens of thousands of children sexually abused in schools, religious organizations and other institutions.

The commission, the highest form of investigation in Australia, urged government action on its 189 recommendations, including the establishment of a new National Office for Child Safety and penalties for those who suspect abuse and fail to alert the police, including priests who hear about abuse in confessionals. It also urged Australia’s Roman Catholic leadership to press Rome to end mandatory celibacy for priests.

“Tens of thousands of children have been sexually abused in many Australian institutions,” said the report, which was particularly critical of Catholic organizations. “We will never know the true number. Whatever the number, it is a national tragedy, perpetrated over generations within many of our most trusted institutions.”

Prime Minister Malcolm Turnbull said all Australians should read the report.

“I want to thank and honor the courage of the survivors and their families who’ve told, often for the first time, the dreadful stories of abuse that they received from people who actually owed them love and protection,” Mr. Turnbull said.