Prison overcrowding has triggered emergency plans for the Northern Territory to shift dozens of inmates but the union for guards is going to court to stop it.
Corrections Commissioner Matthew Varley has ordered a mass prisons move after NT inmate numbers hit a record high of 2370 on Friday.
The record numbers have put "significant pressure" on Darwin Correctional Centre, Alice Springs Correctional Centre and police watch houses.
Mr Varley had deemed the current situation posed extraordinary risks that required immediate action, the NT government said.
Under his directions, 10 extra prisoners will be placed into the Darwin watch house, 20 more inmates sent to Darwin prison and 20 others added to the Alice Springs Reintegration Facility.
All female prisoners at Alice Springs prison will be temporarily transferred to sector 4 of Darwin prison until a new women's facility in Alice Springs is operational.
Another 40 male inmates are to be housed at a "hotel block" within Alice Springs prison, and pressure relieved "accordingly" on Katherine, Palmerston and Alice Springs watch houses.
The first stages of the plan were expected to be put in place this weekend.
"The Department (of Corrections) is developing operational plans to implement these changes and to ensure necessary staffing levels and security in the correctional centres," the NT government said.
"The safety of correctional officers remains a top priority throughout this process."
The United Workers Union, which represents NT correctional officers, is disputing the emergency actions under its enterprise agreement.
The union's NT secretary Erina Early, who visited Darwin prison on Sunday to talk to members, said it would take the matter to the Fair Work Commission.
She said officer shortages were at "crisis levels" and accused the department of breaching safe staffing levels by putting more prisoners in the centres.
"The place is exploding with prisoners yet there is no mitigation or safe process in place," she told AAP.
"The government actions of 'just lock them up' so their crime stats look good is irresponsible and putting the lives of NT correctional officers at risk."
The newly elected Country Liberal Party government, under Chief Minister Lia Finocchiaro, pushed changes to bail and weapon laws through parliament on October 16.
A key election promise, the changes extend police powers to search and seize weapons from anyone over the age of 10 and give all violent offenders a presumption against bail.
Dozens of inmates rioted in Alice Springs prison in January, using bed frames and fans as weapons after a plan to lure a guard into a cell failed.
Two prisoners were taken to hospital for medical treatment and two dormitories that house 10 to 15 prisoners each were damaged.
A 2022 report by the Justice Reform Initiative found incarceration rates in the NT were four times the Australian average for adults and five times higher for children.
Prisoner numbers had grown by more than 30 per cent over a decade, with the number of Aboriginal and Torres Strait Islander adults in prison rising 34.4 per cent.
