A female worker is in hospital after she was allegedly "charged" at by three boys at a western Sydney detention facility.
A witness said that the youth worker was allegedly bashed and kicked on the head before she managed to crawl into a toilet and lock the door at the Cobham Juvenile Centre in St Marys on Sunday afternoon.
A NSW Police spokesman said "police were told several inmates had assaulted a number of staff members before damaging property".
"The inmates were restrained by staff, and several staff members were treated at the scene for minor injuries and taken to Nepean Hospital," the spokesman said.
No charges have been laid yet.
The brutal assault is the latest in a recent string of serious complaints against the facility, which caters to boys aged 15 and older.
In August, two inmates climbed onto the roof and remained there for nine-hours, while in June the Chisolm wing was closed one-year after its opening following complaints the juveniles were excessively isolated.
The facility confirmed that an incident had taken place and they were offering every assistance to the youth worker, who remains in hospital.
"Juvenile Justice staff intervened and de-escalated the situation," a statement from the facility said.
"Police are investigating the incident and the three detainees are likely to be charged.”
Julie Bond, of the Public Service Association, told 2GB today, that the three detainees assaulted the worker leaving her with facial injuries.
"What I understand is that the officer was assisting the detainees who had come back from rec [recreation] leave," she said.
"There was an incident where they actually charged this female officer. Other staff were on the scene very, very quickly, and obviously intervened, but unfortunately an officer has still been injured."