The King's School in Parramatta is the subject of a police investigation after allegations of indecent and physical assault were made by a group of boarding students.

Police confirmed that detectives from the child abuse squad are investigating assault allegations made by students against other students at a school in Sydney's north-west.

"Given those alleged to be involved are juveniles it would be inappropriate for police to provide any further detail at this point in time," a statement from the police media unit said.

It is understood that the allegations centre around indecent and unwanted sexual contact, which include the act of "turkey slapping", where a male rubs his genitals on another's face.

The headmaster of the private boys' school, Dr Tim Hawkes, confirmed that police were investigating the allegations made by students.

"The school has been made aware of an allegations and is co-operating with the police over this matter," Dr Hawkes told the Daily Telegraph.

In accordance with mandatory reporting requirements, all schools are required to report to authorities any incidents where a child may be at risk.

The school was unable to be reached when contacted for comment on Sunday.