A teenager molested by Christian Brother John Laidlaw in the 1980s has told a Melbourne court he thought he was being "punished by God" when he was sexually assaulted at his family home.

Key points: Laidlaw has pleaded guilty to seven historical charges, including sexual penetration

Laidlaw has pleaded guilty to seven historical charges, including sexual penetration A court has heard the church knew of his "improper conduct" but allowed him to keep teaching

A court has heard the church knew of his "improper conduct" but allowed him to keep teaching He abused his position as a teacher and coach, the court has heard

The man is one of six victims sexually assaulted by Laidlaw from 1963 to 1984 when he taught at a number of Catholic schools, including St Joseph's in Warrnambool and Parade College in Bundoora.

Brother Laidlaw taught all six boys who were aged between 12 and 17 when they were assaulted.

The men cannot be identified for legal reasons.

In a victim impact statement read to the County Court, the victim known as Master 16 said he lost his innocence when Brother Laidlaw forced him to perform oral sex when he was home sick one day.

"He broke me in a million pieces," he said.

"I trusted him. I respected him. He made a conscious decision to betray that trust.

"I thought I was being punished by God."

Laidlaw pleaded guilty to seven charges including indecent assault and sexual penetration.

The court heard he abused his role as a teacher and as a sports coach, using the boys' injuries as an excuse to offer sports massages, which became abuse.

"He was scared and confused as to why the offender was touching his genitals," prosecutor Diana Piekusis told the court about Master 13.

Laidlaw wrote letters to victims

One complainant was 12 years old when he was assaulted by Laidlaw after being injured during a football game.

Six years later, the complainant told his father of the assault, the court heard.

But the court heard that his father, who was also a police officer, laughed at him.

Master 17 addressed the court, saying he had flashbacks of the time and that his mother struggled with learning "what she suspected".

At the end of his speech, he turned to Laidlaw in the back of the court and said: "I genuinely forgive you. Shalom."

Shalom is the Hebrew word for peace.

The court heard Laidlaw took a sabbatical in the US in the early 1990s, to get his life in order, undertaking a 12-step program to deal with alcohol abuse and his sexual addiction.

It was during that time Laidlaw wrote letters of apology to two of the boys.

Each letter praised the boy's courage and honesty, and apologised for "the hurt you have been caused".

In 2017, when he was interviewed by police over the charges, the court heard he downplayed the letters, saying he did not recall many of the acts he was accused of.

Laidlaw continued to teach after being found 'unfit'

The court was told the Catholic Church received a "visitation" report in 1973 after Laidlaw left St Patrick's College in Ballarat.

That report determined that Laidlaw was "unfit for the job" after "revelations of improper conduct" and "serious acts of indiscretion."

Laidlaw taught at at least eight more schools before retiring in 1993.

Defence lawyer Simon Moglia admitted that by the 1980s Laidlaw's "conduct had clearly escalated leading to charges of a more serious nature".

He also acknowledged the fact the boys had to "continue in school each week to deal with Brother Laidlaw added to the harm and the difficulties caused to them".

"It is a shame to all of us that the community and those around the victims have not understood that and have not heard complaints as they should have been heard," Mr Moglia told the court.

"[Laidlaw] too at the time of the offending did not appreciate — like many of us — the gravity of the consequences of these actions."

He said his client admitted there was a "clear breach of trust ... clear indecency and sexual assault".

Judge Peter Berman will sentence Laidlaw on July 18.