Seven years ago, William Starr pleaded guilty to sexually assaulting 10 young boys. Now, he's admitted the number is much higher.

The former administrator of a residential school northeast of Regina said on Monday he may have abused hundreds of young boys over a 40-year period.

Starr is the central figure in one of Saskatchewan's most notorious cases of residential school sexual abuse. He has admitted sexually abusing students across the country from 1950 to 1986.

Starr and the federal government are being sued by other students alleging abuse.

The Saskatchewan Court of Queen's Bench is hearing these abuse claims.

The man says some of that abuse took place in Starr's house. And that is what the former school principal is denying.

Starr, who's been flown in from New Brunswick to testify, says he never abused a child in his home. And his wife is backing him up.

Starr's victims have testified their principal never forced them into the abuse.

They say he seduced them with treats and favours such as letting 10-year-olds steer a school bus. There are other reports of abuse in the school's dorms, in Starr's office and steam tubs.

But Starr isn't the only person guilty of abusing students at residential schools in Canada.

There are more than 2,000 lawsuits filed by people who say they were sexually abused while attending residential schools.

Most of the cases have been settled out of court.