The royal commission turned its focus to Geelong Grammar, where serious and ongoing sexual abuse occurred from the late 1950s until 2007.

Former student and Sydney psychiatrist Dr Robert Llewellyn-Jones told the commission on Tuesday that the school's chaplain, the now deceased Reverend John Davison, befriended him in 1971 and then tried to hypnotise him with a watch in his locked office.

Reverend Davison then indecently assaulted him, before accusing Dr Llewellyn-Jones of propositioning him.

"There was a subculture of brutality," he said.

He was also relentlessly bullied by classmates, who called him names, intimidated him and on one occasion made him eat dog poo.

Dr Llewellyn-Jones testified that a classmate sexually abused other students, and painted one student's genitals in shoe polish. He said he was scared that he would be picked on next.

"The abuse I have described was rooted in a subculture of bastardisation that dates back to the culture of the great public schools of the 19th to mid 20th century in Britain and Australia," he said.

The psychiatrist, who now helps other abuse victims, said it was deeply concerning that there had been no consequences for the perpetrators. He said he never reported his abuse because of a "deep code of silence" that pervaded the boarding school.

"The power and prestige of the school served to discourage victims from breaking their silence about the abuse that they experienced," he said.

The two-week public hearing will focus on Geelong Grammar's response to five employees convicted of child sexual abuse. It will hear from 23 witnesses, including six former students, three former principals and the school's current principal, Stephen Meek

Another victim, known only as BKU, painfully recounted how house tutor John Buckley offered to help him remove body paint after a drama performance and stroked the victim's genitals.

Mr Buckley, who later went on to be a well-known art dealer, recently admitted to abusing six boys at the school and will soon be sentenced.

BKU also alleged that Reverend Norman Smith, now deceased, sexually abused him in 1967 at the school's Timbertop campus for year nine students. He pointed out that it occurred a year after Prince Charles attended the rural campus.

"The environment at Geelong Grammar was so heavily steeped in a punishing culture devoid of pastoral care that I never raised the issues while at school."

He blasted the school over its handling of his abuse, saying it did not respond appropriately to a letter he sent in 2014.

"They have failed morally and have shown themselves to be two-faced and self-serving."

Graham Dennis was employed at the school in the 1950s and in 2008 was charged with gross indecency and indecent assault on a male student.

Jonathan Harvey, who worked at the school's main campus at Corio, on the outskirts of Geelong, up until 2004, pleaded guilty in 2007 to 10 counts of sexual abuse and gross indecency with a male student.

In 2005, former Geelong Grammar tutor Philippe Vincent Trutmann was sentenced to up to six-and-a-half years in jail for sexually abusing 40 young male boarders at the school's Highton campus between 1985 and 1995.

He was also charged with possessing 485 images and 159 videos of child pornography.

In his opening address, counsel assisting David Lloyd said the school became aware of Mr Trutmann's sexual abuse in 1985 or 1986, and again in 1992.

"After these matters came to the attention of the school between 1985 or 1986 and 1992, Trutmann went on to sexually abuse more children at the school," Mr Lloyd said.

He would go into the boy's rooms at night and sexually abuse them while they slept, he said

"Sometimes the boys did not wake. At other times they were awake but did not move because they were frozen with fear."

Mr Lloyd said evidence would be heard that "very senior staff, knew about a number of allegations of sexual abuse at the school at or around the time the abuse was occurring,"

The two-week hearing will also hear about the school's response to Stefan van Vuuren, who in 2007 took photos up the skirts of female students while on an excursion.

The school did not appear to have any written policies or procedures regarding child sexual abuse before 1993 or 1994, the commission heard.

Geelong Grammar was established in 1855 and is Australia's largest co-ed boarding school, with more than 1500 students.

The hearing continues.