The ACT Supreme Court's drug and alcohol sentencing list has saved up to $14 million that would otherwise have been spent locking people up, the Australian National University study found, more than offsetting the roughly $13.3 million recently allocated to run it for another two years.

Chief Justice Lucy McCallum and ACT Attorney-General Shane Rattenbury released the independent review on Tuesday, when the latter expressed a desire to expand the scheme after it hit capacity in recent months and had to stop taking new referrals.

The ANU study, conducted by six academics, shows 56 people have been sentenced to drug and alcohol treatment orders since the option became available to judges in December 2019.

Treatment orders can be imposed as part of jail sentences between one and four years in length, with the custodial component suspended in favour of programs that often involve stints in residential rehabilitation and regular reviews by the supervising judge, Acting Justice Richard Refshauge.

Fifteen offenders with entrenched addiction issues have had their treatment orders cancelled because of non-compliance, while more than half of the people sentenced to one are still completing their programs.

Treatment orders now last an average of 21 months.

Eight people, sentenced to treatment orders for offences as serious as aggravated robbery, have graduated from the scheme and never come back before the courts.

Mr Rattenbury said it was clear the sentencing list scheme was reducing reoffending, helping offenders get their lives back on track, and saving the community money.

The Attorney-General added that the fact the "transformational" program had hit capacity was a measure of its success and an indication of the need to keep funding it.

"[The ANU] report provides strong evidence to both continue to program and to expand it," he said.

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"Certainly, I'll be making the case in the budget process for an expansion of resources so that we can have more people coming to this program.

"This program very much matches the [ACT] government's goal of building communities, not prisons.

"This is where we want to be spending our money, not on building a bigger jail, but on investing in the programs that help people get out of the criminal justice cycle and actually put their lives on a different track."

Veteran Canberra defence barrister John Purnell SC, who has publicly pushed for the program to be better resourced, welcomed Mr Rattenbury's remarks.

Mr Purnell said he hoped to see the program's capacity doubled, telling The Canberra Times at least 85 per cent of his clients who had committed serious crimes had drug problems.

"The most effective way of treating drug addicts, or people who commit crimes with drugs, is the drug court," he said.

Mr Purnell added that expanding the program was "a no brainer" when the ACT was the most expensive place in Australia to incarcerate a person.

"We're $528 a day. The national figure is $375, and the drug court is a much cheaper alternative," he said.

"So, just from an economic point of view, it's a benefit rather than a negative."

Chief Justice McCallum described the review as "good news", saying it showed drug and alcohol treatment orders were effective sentencing options that were treating addictions and reducing recidivism.

"And the court's sentencing options should always be evidence-based, so that's a great boon to the court," she said.

The ANU review makes 39 recommendations, which include that the eligibility criteria for offenders be "revisited" to ensure the program is "enrolling the appropriate target cohort".

Chief Justice McCallum said she did not think the roughly 27 per cent cancellation rate meant the criteria needed to be narrowed, saying she thought they should in fact be expanded in order to open the door to, for example, people on shorter sentences.

The report also recommends action in areas like housing, recommending the government invest in accommodation options for people at risk of homelessness because of addiction.

"The lack of housing many participants face is a significant hurdle to entry onto the program and likely impacts on the chances of sobriety and successful completion, once they are on the program," it said.

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