A number of inmates damaged building fixtures and furniture before they climbed onto the facility's roof, where they spent the night in near-freezing temperatures. Armed with large bits of wood, inmates on the roof were dancing and hitting tennis balls to one another with racquets on Monday morning. Riot police at the scene on Monday morning. Credit:AAP Families and Communities Services Minister Gareth Ward on Monday night said the incident was "unacceptable". "We are treating it very seriously," he said. "Our priority is the safety and wellbeing of staff and detainees involved ... Actions that put the safety and security of staff and detainees at risk will not be tolerated. "

Emergency services were called about 8.30pm on Sunday and heavily armed police established a perimeter around the entire facility. A Corrective Services source told the Herald that the detainees attacked fellow inmates including prisoners in the facility for sex offenders, and police had to use gas in a bid to restore order. The source said staff were fearful for their safety and unable to intervene until police arrived. Loading An 18-year-old, who suffered stab wounds and facial injuries, was taken by NSW Ambulance paramedics to Royal North Shore Hospital in a serious condition. Another 18-year-old suffered stab wounds to his head and hands, a 20-year-old suffered facial and hand injuries, a 17-year-old had facial and head injuries, and another 20-year-old suffered injuries to his hand, leg and arm. Another 17-year-old dislocated his ankle after jumping off a roof. They were all taken to Gosford Hospital.

A seventh juvenile was treated later at the scene for a broken nose. Nine detainees surrendered peacefully throughout the day and the remaining inmates surrendered just before 5.30pm when police gained access to the roof. Twenty men, aged between 16 and 20, were arrested and remain in custody. Inmates are seen on the roof of Frank Baxter Juvenile Justice Centre at Kariong during the riot. Credit:AAP Superintendent Tony Joice, district commander of Brisbane Water Police, said it appeared to be a "a very sudden and unprovoked incident".

He said police had "used a number of resources including PolAir, the dog squad, rescue squad, a number of specialist resources from Sydney, and the operations support group from the northern region, to safely resolve this as quickly as possible". Reports that a chainsaw had been used in the riot was "a myth", he said. Detainees are seen during a riot at the Frank Baxter Juvenile Justice Centre, Kariong, on Monday. Credit:AAP Juvenile justice system 'irrefutably now in crisis' The chaotic scenes from Sunday and Monday were "not an isolated incident" and should be seen as a symptom of an under-resourced juvenile justice system that is in crisis, the Public Service Association, which represents staff at the Frank Baxter facility, said.

The facility, which opened in 1999, is the largest juvenile detention centre in the state, capable of housing up to 120 inmates between 16 and 21. Loading It has been plagued with recent incidents, and staff walked off the job a month ago following an assault that left a prison officer with concussion, a broken nose and a broken eye socket. From 2017 to 2018, physical assaults on staff, ranging from spitting to violent attacks, jumped from eight to 25, while self-harm incidents doubled, rising from 52 to 100. Incidents requiring medical help or hospitalisation rose from 30 to 49. PSA general secretary Stewart Little said the juvenile justice system "is irrefutably now in crisis" and it is "only by the grace of God" that someone has not been killed.