The lack of structured activity left prisoners at risk of boredom, undermining their rehabilitation, with the potential to encourage drug use and risk security and safety, Auditor-General Maxine Cooper reported on Friday, finding that rehabilitation and education at the prison had fallen far short of expectations.

Dr Cooper found "a very large gap between what was anticipated and what has occurred" since the prison was opened, in the numbers of prisoners, the kinds of prisoners and the programs delivered.

Her report sheets home much of the blame on overcrowding at the centre, which has been over-capacity for most of its life. Rehabilitation work was compromised by the overriding challenge for management of finding accommodation for detainees and keeping them apart - with the arrival of one new detainee forcing the movement of up to 10 others.

Dr Cooper's audit also highlights a lack of planning for rehabilitation and a lack of data on how prisoners spend their time. With no performance measures for rehabilitation there was no way to determine whether rehabilitation was being achieved, and whether reoffending rates were being reduced, she said.

She focused on three major programs at the Alexander Maconochie Centre targeting family violence program, "cognitive self-change", and adult sex offenders (with others in area such as drug and alcohol programs and anger management). Only about one in five detainees was in one of the main programs.

From 2012 to 2014, between 2 and 5 per cent of prisoners took part in a family violence program, compared with a planned 50 per cent. No other violence programs were offered, despite violent offenders being a priority when the prison opened. Between 9 per cent and 14 per cent of offenders had taken part in the cognitive self-change program, far fewer than the 90 per cent envisaged; and between 3 per cent and 9 per cent had been part of an adult sex offender program, a little less than the predicted 10 per cent.

Dr Cooper offered comments from detainees, which ranged from claims prisoners were forced to do programs simply for parole, to "the best thing that he has ever done" at "the best rehabilitative jail he has been in".

She also found that just 41 per cent of prisoners were in work, and no records were kept of hours worked. Most of the jobs were domestic - cleaning, sweeping, emptying bins and serving food. A plan to run prison-based industries was yet to eventuate, and work that helped people learn skills for life outside prison had been very limited.

The audit said 74 per cent of prisoners were enrolled in vocational education and training in June last year, well up on predictions, but the average time spent in education across the prison was fewer than two hours a week, compared with the 15 to 25 envisaged.

Dr Cooper said the plan for "structured days" was not being realised. The plan had been organised activities six hours a day of activities, five days a week,

"However, fewer than one in two male detainees is in employment and for those who are, the time spent in work is indeterminate," she found. "Regardless of whether or not a detainee is working, their 'structured day' generally comprises no more than one hour a week on average in therapeutic programs and only approximately two hours a week is spent with family and other visitors; and an average of two hours a week is spent in education."

Prison officers said the planned structured day had not eventuated because the philosophy was not to compel people to take part.

But the audit quoted one prisoner as saying all they had to do was "work out and play cards"; another saying he was in a yard with 40 men and just four jobs; and other saying that other jails had a better routine.

The Justice and Community Safety directorate said by focusing on just three programs, the audit office had not made a "coherent examination of all rehabilitation service delivery".

The prison had a significantly more complex environment and case load than envisaged in 2007, making the aspirations of 2007 unachievable, it said. Energy had been focused on managing the high detainee numbers.