A five-year inquiry into sexual abuse in Australia has released its final report, saying institutions had "seriously failed" to protect children, BBC news reported Friday.

The royal commission, Australia's highest form of public inquiry, heard more than 8,000 testimonies from victims of abuse.

The accusations covered churches, schools and sports clubs over decades.

Among more than 400 recommendations, the report calls on the Catholic Church to overhaul its celibacy rules.

"Tens of thousands of children have been sexually abused in many Australian institutions. We will never know the true number," the report said.