Retired pope Benedict XVI has asked for forgiveness for any "grievous faults" in his handling of clergy sex abuse cases, but admitted to no personal or specific wrongdoing.

His statement came after an independent report criticised his actions in four cases while he was archbishop of Munich in Germany.

"I have had great responsibilities in the Catholic Church. All the greater is my pain for the abuses and the errors that occurred in those different places during the time of my mandate," the retired pope said.

Benedict, 94, was responding to a report on January 20 from a German law firm that had been commissioned by the German church to look into how cases of sexual abuse were handled in the Munich archdiocese between 1945 and 2019.

Benedict, the former cardinal Joseph Ratzinger, headed the archdiocese from 1977 to 1982.

The report's authors faulted Benedict's handling of four cases during his time as archbishop, accusing him of misconduct for having failed to restrict the ministry of the priests in the cases even after they had been convicted criminally.

The report also faulted his predecessors and successors, estimating that there had been at least 497 abuse victims over the decades and at least 235 suspected perpetrators.

The Vatican released a letter Benedict wrote to respond to the allegations, alongside a more technical reply from his team of lawyers and advisers who had provided an initial 82-page response to the law firm about his nearly five-year tenure in Munich.

The conclusion of Benedict's advisers was resolute: "As an archbishop, cardinal Ratzinger was not involved in any cover-up of acts of abuse," they wrote.

Furthermore, they said, the report provided no evidence that Benedict was aware of the criminal history of any of the four priests in question.