NT Attorney-General Natasha Fyles has ordered an immediate increase in drug and alcohol testing for parolees after four people were killed in Darwin three weeks ago by a gunman who was on parole.
A review of the Territory's parole system, ordered after the shooting rampage, found many parolees breaching conditions and not being properly drug or alcohol tested.
However, Commissioner for Corrections Scott McNairn, whose department produced the the audit, said it had found no serious issues in the parole system or risk to the public given the majority of people were being properly tested.
Chief Minister Michael Gunner asked for the "urgent audit" after it emerged alleged killer Ben Hoffmann, 45, had been released on parole this year and had an electronic bracelet, alarming many people.
Hoffmann has been charged with four counts of murder for the alleged shooting of cabbie Hassan Baydoun, 57-year-old Michael Sisois, New Zealand security guard Rob Courtney and 76-year-old Nigel Hellings during a 28-minute rampage in Darwin on June 4.
It was the Territory's worst-ever mass shooting.
The audit found 85 per cent of people on parole in the NT and 83 per cent being monitored with electronic bracelets were being tested for alcohol in line with their conditions.
The levels of drug testing for parolees and people being monitored were 83 per cent and 84 per cent.
Significant numbers of offenders were not being tested as required, although Ms Fyles said some of those people were difficult to get to in remote communities.
"I have directed the Department of Attorney-General and Justice to immediately increase the frequency of drug and alcohol testing for offenders, particularly high risk," she said.
After the shootings, Mr McNairn said he was "saddened that it has happened" and confirmed his department had recommended the alleged killer's release to the independent Parole Board.
The review's eight recommendations call for increased resources such as funding for the Corrections' department's drug and alcohol testing and auditing capacities.
A Coronial inquest into the recent shooting deaths would be independent and investigate any flaws in the parole system and any other government agencies, Ms Fyles said.
Australian Associated Press