A Catholic school in Dunedin has been accused of a historic cover-up, after a teacher who sexually abused pupils for more than a decade took his own life when finally confronted, victims say.

Three men - all former pupils at St Paul's High School in Rattray St - have told ODT Insight the teacher, Ian Thompson, targeted pupils at the school throughout the 1970s and into the 1980s.

Two of his victims, Paul Klemick and Michael Haggie, agreed to go public about their experiences with Thompson, amid suggestions he abused at least 16 boys from the school.

"I think he was a predator," Haggie said. "He just preyed on young boys who were very innocent."

Haggie said he was abused daily by Thompson throughout his senior years at the school, beginning in 1971 when he was 15.

Klemick said his abuse started soon after he arrived as a 12-year-old in 1979, and continued throughout his four years at the school.

Both men said Thompson targeted other boys too, and Klemick said he was once forced to perform sex acts on another boy while Thompson watched.

And, when Klemick finally confronted Thompson, the teacher, fearing his secret would be revealed, took his own life, Klemick said.

The school - which has since been replaced by the Catholic co-educational Kavanagh College - was at the time run by the Christian Brothers, a Catholic religious order.

Former pupils say the teacher, Ian Thompson, targeted pupils at the school throughout the 1970s and into the 1980s. Photo / Supplied

The Christian Brothers had employed Thompson after he was forced out of a Marist Fathers seminary in the North Island, allegedly after affairs with other seminarians, a third pupil said.

But, in the days following his death on January 15, 1985, staff at the school were told to keep quiet about any suggestion of suicide.

A former St Paul's staff member, speaking on condition of anonymity, told ODT Insight there had been "considerable" unease among staff about the behaviour of Thompson and the nature of his death.

"I was there when the principal told all staff to say that the death was not a suicide," the former teacher said.

Instead, Thompson's death was presented as a heart attack at the time, and he was farewelled at a big funeral at St Joseph's Cathedral, the victims said.

A brief coroner's report from June 1985, obtained by ODT Insight yesterday, confirmed Thompson's death was self-inflicted.

Haggie believed some of the Christian Brothers at the school suspected Thompson, "but they never came up with an accusation".

That left Thompson free to behave as if it was "open season".

"He just saw he could get away with whatever."

Klemick said Thompson also kept nude photographs of his victims in a box at his home, including some of Klemick.

But, when Klemick let himself in after learning of Mr Thompson's death, he found the pictures were gone and the rest of the house was uncharacteristically tidy.

When he relayed his concerns to another teacher at the school, he was told not to say anything to police, he said.

Haggie said events took another turn when it later emerged Thompson had left his home and possessions to another former pupil from the school.

The school and the Christian Brothers order which founded it were already in the spotlight after ODT Insight last month revealed more details of offending in Dunedin.

That included the activities of the paedophile priest Fr Magnus Murray and fresh allegations of abuse against Br Desmond Fay and a second Christian Brother, who cannot yet be named.

All three men were employed by the Christian Brothers to teach either at St Paul's or the Christian Brothers Junior School in the 1960s or 1970s, before Thompson joined St Paul's.

The St Paul's principal at the time, Br Tony Gherardi, has since died, and St Paul's was replaced by another Catholic school, Kavanagh College, in 1989.

Dunedin Bishop the Most Rev Michael Dooley told ODT Insight the diocese had no record of complaints relating to Thompson, but he was "shocked and deeply saddened" by the allegations.

The school's board of governors was responsible for employing Thompson, but the alleged offences should be investigated, Bishop Dooley said.

That could be done by the police, the church's National Office for Professional Standards or as part of a pending Royal Commission into historic abuse, he said.

Kavanagh College principal Tracy O'Brien said he had not been approached by anyone with allegations of historic offending by Thompson, or anyone else at St Paul's High School.

"To the best of my knowledge neither has any staff or board member during my tenure," he said.

O'Brien said he supported Bishop Dooley's recent public apology for the impact of historic sexual abuse and the church's handling of it, and would "continue to look to the bishop's leadership on any historical matters".

A New Zealand Police spokeswoman declined to comment, and the Government is yet to confirm the scope of its Royal Commission.

Where to get help:

• If it's an emergency and you feel that you or someone else is at risk, call 111.
• If you've ever experienced sexual assault or abuse and need to talk to someone call the confidential crisis helpline Safe to Talk on: 0800 044 334 or text 4334.
• Alternatively contact your local police station
• If you have been abused, remember it's not your fault