Northern Territory Police are investigating the circumstances of a disturbance at the Alice Springs Correctional Centre on Friday afternoon which involved more than 50 prisoners.
NT Corrections commissioner Matthew Varley said staff were still cleaning up after a group of inmates started fires and caused damage to doors, locks and windows in accommodation blocks at the facility.
NT Police Commander Craig Laider has confirmed that police are investigating the incident.
He also said some prisoners had been moved to the Alice Springs watch house afterwards, with some still there on Sunday afternoon.
"Northern Territory police are temporarily housing a group of prisoners at the Alice Springs watch house," Commander Laider said.
"Corrections staff are managing the prisoners at the watch house."
While police did not specify the number of prisoners currently being held, United Workers Union NT Secretary Erina Early, whose union represents corrections officers, said at least 56 prisoners had been relocated to the watch house after the disturbance.
"The ones who instigated have been removed from the prison," she said.
The ABC understands there are currently 617 prisoners at the Alice Springs Correctional Centre.
The facility has the capacity for 650 inmates.
Mr Varley said corrections officers were still working to resume normal operations at the Alice Springs facility.
"There is still a bit of clean-up work to do," Mr Varley said.
"Our officers have worked tirelessly to ensure the ASCC is safe and secure, prisoners are well cared for, damages are assessed and repairs commenced."
The disturbance at the prison happened the same day as NT police officer Zachary Rolfe was found not guilty of murder and two alternate charges over the fatal shooting of Indigenous man Kumanjayi Walker in Yuendumu in 2019.
Staff held concerns for their safety, union says
Mr Varley said no staff had been injured in the effort to bring the incident under control.
"Thankfully, only one prisoner was treated for minor smoke inhalation," he said.
However, Ms Early said staff had been concerned for their safety, and corrections officers had to deploy gas while trying to bring the situation under control.
"Officers did have to use gas. I'm not sure what gas was used or the excess of use.
"The information hasn't been shared."
Ms Early said the situation was especially concerning in light of a long-standing staffing issue at the prison.
"The staffing levels at Alice Springs have been at crisis level for a very long time and when you have something like this, it really hits home," she said.
"They're pretty exhausted."
