Sr Mary Theresa Grogan, formerly known as Sr Peter, has pleaded not guilty to 63 charges of indecently assaulting seven young girls, mostly in a classroom in the school between 1973 and 1977.

The court was told by the prosecution that the abuse was systematic, all the alleged victims were the same age, they were third class pupils.

It heard that the assaults were repetitive and similar with the girls being called up to the nun's desk when it was time to correct homework.

Sr Grogan, 62, spent time in the missions in Africa but when she returned a number of years ago, one of the alleged victims made a complaint to gardaí who began an investigation.

The trial before Judge Donagh McDonagh is expected to continue for two to three weeks.