The Northern Territory's overcrowded jails are at a "critical tipping point" with widespread drug use, failing rehabilitation programs and staff resistant to reform, the head of the parole board says.
Calls for change have been ignored and NT government policies are inconsistent as parole rates and funding for support programs fall.
"The environment in which the Parole Board functions is also becoming increasingly difficult," Supreme Court Justice Stephen Southwood said in the board's 2019 annual report, tabled in the NT parliament on Thursday.
"Prisoners are not being adequately prepared for parole."
For most of 2019, there were more than 1800 prisoners in the NT's two major correctional facilities and work camps, which is about seven per cent above capacity.
The Parole Board examined 1351 prisoners' cases in 2019, with 155 prisoners granted parole - three fewer than in 2018 and six less than 2017.
"The operation of the two correctional centres in the NT is reaching a critical tipping point," said Justice Southwood, who chairs the NT Parole Board.
Prisoners' use of synthetic cannabis - known commercially as Kronic - was "becoming more widespread", he said.
There are also insufficient rehabilitation resources, and a number of significant industrial issues have not been resolved, with some correctional staff resistant to necessary reforms.
"The number of hours prisoners are spending in their cells has significantly increased," Justice Southwood said.
"Despite the completion of a number of very detailed reviews of the Northern Territory Correctional Centres, which have recommended significant reforms to the operation of the two centres, government policy continues to lag significantly behind what has been recommended and remains ad hoc."
Funding for the North Australian Aboriginal Justice Agency parole support has also ended and it's possible funding for some residential community rehabilitation facilities could be withdrawn.
"This is a great loss," Justice Southwood said.
NT Attorney-General and Justice Minister Selena Uibo said the NT's Corrections Department budget would be carefully considered to ensure staff were provided with the resources and support they need.
"However, high imprisonment rates come at a significant economic and social cost and that's why the Territory Labor Government is working to ultimately reduce imprisonment rates and reoffending," she said
About 85 per cent of NT prisoners are Indigenous.