Elite Vic school aware of abuse: victim

A former student has accused staff at an elite Melbourne school of turning a blind eye while he was sexually exploited by a teacher.

Former Ivanhoe Grammar teacher Graeme Harder, 60, pleaded guilty at the Victorian County Court on Thursday to 12 charges of sexually penetrating a student under his care during the early 1990s.

The charges are representative of numerous sexual acts with the boy that began in 1991, when the boy was 15 while Harder was 37.

Harder had sex with the boy multiple times on school grounds and during overnight school trips.

The teacher told the student their relationship was like a marriage and that he loved him.

The victim, now 40, was teased about how close he and Harder were by other students and teachers.

"It was obvious and why the school didn't intervene baffles me now," he told the court.

"They allowed things to go on unquestioned."

There was weekly sexual activity between teacher and student, who were both part of Ivanhoe Grammar's extra-curricular scuba diving program.

Harder used to leave notes in the victim's locker with messages like "let's have a splash", which meant he wanted to meet the boy in the school's scuba room to have sex.

The victim would also meet Harder at his home in Eltham North while his wife was away.

After Harder had sex with the boy for the first time during a school trip to Apollo Bay, Harder told the boy what they had done was normal.

The student did not report the sexual abuse until last year, when he contacted police.

Harder continued working at Ivanhoe Grammar until he was charged with 33 historic sex offences on March 4, 2015.

He has been remanded into custody for sentencing on October 8.