The King's School in Parramatta was ineffective in dealing with the sexual assault and bullying of a student at a cadet camp in 2013, the Royal Commission into Institutional Responses to Child Sexual Abuse has found.

In a report released today, the commission said senior management at the elite Sydney private school failed in their handling of an allegation that a student masturbated on another student's sleeping bag.

Over the following months, the then-Year 10 student, known as CLC, was bullied by students, who called him "cum rag" and "cum dumpster".

On one occasion, the King's Wi-Fi network was renamed "CLC is a cum rag".

During public hearings in October and November 2016, the commission heard CLC disclosed the cadet camp incident and the bullying he was experiencing to staff at King's in August 2013.

Deputy headmaster Dr Andrew Parry conducted an investigation into the camp incident and the bullying, which broadly confirmed CLC's allegations.

Dr Andrew Parry was deputy headmaster of the Kings School in North Parramatta. ( Linked In: Dr Andrew Parry )

Following a telephone conversation, a police officer told Dr Parry a criminal act had been committed and that the incident should be reported to police. However, no report was made.

The commission found this was "a failure by the senior management of King's".

Headmaster Dr Timothy Hawkes "candidly" accepted that the steps King's took were not effective in this case, the commission said.

Dr Hawkes also accepted that, despite the steps King's had taken, a "not insignificant" number of boys continued to bully CLC.

CLC then left King's and attended another private school, St Ignatius College, Riverview.

The commission said staff at Riverview took a daily interest in how the student was coping.

It also said anti-bullying measures at the school were more appropriate and successful at preventing bullying than those at King's.

The King's School principal and former Knox Grammar teacher and boarding master Dr Timothy Hawkes. ( AAP: Dan Himbrechts )

Trinity boarding house examined

Another Sydney private boys' school, Trinity Grammar at Summer Hill, was also examined by the commission.

In 2000, two former boarding students, known as CLA and CLB, were sexually assaulted by other students in the boarding house.

CLB completed an incident report stating that some boarders had tried to "rape" him that day.

He also complained that a boarder had made a "dildo in wood tech" class which was used to "stick up peoples [sic] butts".

The commission found Trinity did not give CLB appropriate support.

He was counselled by then-senior school psychologist, Katherine Lumsdaine, who was so concerned that senior staff would not investigate the allegations that she commenced her own investigation.

Ms Lumsdaine said she uncovered numerous accounts of students being sexually assaulted with the "wooden dildo".

The commission said it was satisfied that if Ms Lumsdaine had not interviewed the boys and reported her conclusion there would have been no investigation of the sexual assaults that were occurring in the boarding house in 2000.

Criminal proceedings were ultimately commenced against four boys in relation to the assaults. Two of the boys pleaded guilty to indecent assault.

Trinity Grammar School spokesperson and council chair, Richard Pegg, said the school "acknowledges with regret that its initial response to the incident of 2000 was inadequate".

Mr Pegg said Trinity had noted the commission's findings.

"The welfare and wellbeing of our boys are paramount and we will consider seriously for implementation all recommendations that the commission makes in its final report," he said.

The commission is expected to hand down its final report with findings and recommendations by the end of the year.