More than 200 children at a famous choir school in Germany run by the brother of Pope Emeritus Benedict XVI fell victim to physical and sexual abuse, an ongoing investigation into the decades-long Catholic Church scandal revealed.

The investigation is centred on the Domspatzen, the official choir at the Regensburg Central dedicated to St. Peter in Bavaria state, and two feeder schools between 1953 and 1992.

Investigators received additional allegations of sexual and physical assault by priests on the members of the boys choir, according to Ulrich Weber, a lawyer hired by the church to look into the scandal.

Weber told a news conference in Berlin last week that at least 50 of the 231 alleged victims made "plausible" claims of sexual abuse.

The alleged sexual abuse encompassed offences such as fondling and rape, while the reported physical abuse included beatings and the withholding of food. He said the victims named 10 perpetrators, Agence France-Presse reported.

The first allegations of sexual abuse were reportedly made public in 2010 when a well-known composer named Franz Wittenbrink told the German magazine Der Spiegel that he had been abused while enrolled at the boarding school.

Between 1953 and 1992, the choir was run by Monsignor Georg Ratzinger, older brother of the resigned pontiff. At that time, at least 2,100 students participated in the choir, said Weber.

"As many as one-third of its participants may have been abused over the years... After my research, I must assume [that Ratzinger had known of the abuse],'' said Weber, adding the events were known internally and criticised but has almost no consequences.

The now 92-year-old priest told German newspaper, Passauer Neue Presse that the boys told him about the physical abuse they suffered at that time at the hands of Johann Meier, head of one of the lower schools, but denied any knowledge of sexual abuse.

He also said that the cases are now too old to be prosecuted. "These things were never discussed. The problem of sexual abuse that has now come to light was never spoken of.''

The new allegations were attributed mainly to Meier, who headed one of two primary schools associated with the choir from 1953 until his retirement in 1992, USA Today reported.

A total 140 people, including 70 alleged victims, have been interviewed during the course of eight months, said Weber, adding that several other alleged victims contacted him since the report was made public.

The Regensburg diocese published the new report on its website Friday last week, along with a year-old homily by Bishop Rudolf Voderholzer in which he reportedly expressed regret for the abuse the children allegedly suffered, according to reports.

Last year, the Church began paying compensation of 2,500 euros ($2, 730) to each victim.

The famous choir group is more than 1,000 years old. The members sing at the Regensburg Cathedral every Sabbath day and also perform in other countries.