A Swiss man has appeared in court accused of drugging and sexually abusing girls at a camp and a private boarding school in Switzerland.

The unnamed man in his early sixties appeared at the district court in the southern town of Brig on Monday to answer charges he molested some fifty girls between 1996 and his arrest in 2007.

Prosecutors accuse him of breaking into the exclusive Alpine boarding school Aiglon College de Villars in 2000 and using a chloroform-like substance to drug three girls aged 15 and 16 before sexually abusing them.

Authorities say he committed similar acts at a camp in the town of Fiesch in 1996.

Investigators matched DNA found at the crime scenes to his when the man was arrested in 2007.

The trial continues.