Former music teacher Leonard Cave, who abused students at Dilworth School in Remuera and St Paul's Collegiate in Hamilton over a span of five decades, was chastised today for minimising his offending as "horsing around" as a judge sentenced him to eight years in prison.

Earlier in the hearing the 75-year-old had sat quietly in the dock as his lawyer, Warren Pyke, read aloud a short apology letter. It was his first time acknowledging some guilt.

"I would like you to know how dreadful I feel," he wrote.

"I somehow imagined that this had been a mutual adventure ... I wish it had never happened. I behaved dreadfully and the bad feelings will haunt me forever."

Organist Leonard Cave. Photo / Supplied

But it didn't address all of his victims and came too little too late, prosecutors suggested.

Jurors in the High Court at Auckland returned guilty verdicts in June - following seven days of testimony - for charges of indecent assault, indecency between males, sexual violation, and supplying cannabis and LSD to students.

Cave had used his career "as a vehicle to prey on young men", prosecutor Jacob Barry told jurors at the end of the trial, pointing out that all six complainants knew his through a teaching relationship.

One of the victims, in a statement read aloud by prosecutors, said it was "utterly indefensible" that Cave "subjected us all to the indignity and trauma" of a trial. After 40 years of trying not to think about his victimisation, he said he's spent the past two years worrying about having to relive it on the witness stand - and the possibility of not being believed.

"You chose to lie. You allowed this to continue, to expose me to a further two years of trauma, anxiety and sleepless nights," he said, adding that Cave could have fallen on his sword when the allegations finally came to light. "You chose self-preservation.

"You deserve everything you get."

Former Dilworth teacher Leonard Cave enters a courtroom dock in the High Court at Auckland as his sentencing hearing begins. Photo / Michael Craig

Among those who testified against Cave was a former Dilworth student who recounted the teacher grabbing his crotch near the school's chapel in the 1970s. He said he complained to the principal at the time but no action was taken.

Cave left the school to travel abroad but was rehired as head of the music department a few years later. In that role, he was accused by four boys of sexual abuse during visits to his bach on Waiheke Island.

The fourth boy told his mother about the abuse, and she reported it to Dilworth. Cave left the school soon after, though it was never referred to police.

Cave went on to teach at St Paul's Collegiate, where he was accused of abusing a student there. The student reported it to police in 2012 and an investigation was started but no charges were laid.

Cave wasn't arrested until the conclusion of Operation Beverly in 2020. The police investigation followed an internal inquiry by the school after it was alerted to historic abuse by a former student.

In all, 12 people associated with Dilworth School have been accused of sexual offending between the 1970s and 2000s. Three of the accused have died, and another three have been convicted.

Cave's case was the first to go to trial.

-  Craig Kapitan and Isaac Davison, NZ Herald