Victoria Police is investigating the alleged assault at a fundraising event at Malvern Town Hall on Saturday night, attended by nearly 600 people, including students from Melbourne's top private schools.

Fairfax Media understands the year 11 Xavier student brutally punched the year 10 Trinity boy in the face while they were on the dancefloor at the fundraiser hosted by art therapy provider, The Art Cabriolet.

• Do you know more? Contact the reporter, Timna Jacks. 

The alleged attack is understood to have been sparked by an argument over a girl, with sources who know the victim saying the perpetrator was attracted to the Trinity boy's girlfriend.

Police say they were told a 16-year-old boy was "struck to the face by another attendee", sustaining a broken nose, concussion and neck injuries.

A person close to the victim's girlfriend said friends of the Xavier boy had held the victim, as he was punched.

He was taken to Epworth Hospital about 8:30pm with upper body injuries, Ambulance Victoria confirmed.

The victim is understood to have been discharged from hospital earlier this week and is recovering at home.

The incident is said to have left the the year 10 student and his girlfriend "traumatised".

Fairfax Media has decided not to name the perpetrator, however police confirmed that the parties were known to each other. Less than 100 metres separate the two private schools in Kew.

The fight was mentioned on 3AW Breakfast's Rumour File earlier this week.

Leading Senior Constable Kendra Jackson said an "investigation remains ongoing and no arrests have been made".

Xavier College principal, Dr Chris Hayes, would not confirm that any Xavier student was involved in the fracas, but said he was in contact with police about the fight, and would co-operate with their investigation.

"Along with many other young people, some Xavier students were present at this non-school function," he said in a statement.

"This incident is very regrettable because any display of violence is totally unacceptable. We teach our students that preventing violence in any situation is everyone's responsibility."

Trinity Grammar headmaster, Dr Michael Davies, said the school has been "constantly [in] contact with the family to ensure we support them in any way possible."

"We understand this is a matter for the police to investigate and do not wish to comment on the incident itself, but we will continue to offer our ongoing support to our student and his family."

Fairfax Media understands a Xavier student hosted the party and was the DJ. He was raising money for his mother's charity, The Art Cabriolet. The venue was hired out by the charity.

Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au.

With Henrietta Cook