Corrections Minister Shane Rattenbury.

Corrections Minister Shane Rattenbury. Photo: Elesa Lee

The descriptions of Canberra's prison as the ''most expensive, most violent, and least secure'' in the country are exaggerated and unfair, Corrections Minister Shane Rattenbury says.

The criticisms of the running of the Alexander Maconochie Centre were made by ACT Opposition Leader Zed Seselja on Thursday, based on new data released in the Productivity Commission's Report on Government Services.

The report showed the ACT recorded the highest number of assaults in custody in the nation, the highest number of breakout attempts, and the highest cost per prisoner.

ACT Liberal leader Zed Seselja.

ACT Liberal leader Zed Seselja. Photo: Karleen Minney

Those statistics, which the Productivity Commission warns against comparing across jurisdictions, may be influenced by the ACT's relatively small number of average daily prison population of 259.

That compares, for example, with NSW's average prison population of 9,752, Victoria's 4,831, and South Australia's 2,078.

Mr Seselja described the statistics as a ''dreadful result for the territory. The prison should be an important part of our law and justice system; instead it is simply the most expensive, most violent and least secure in the country,'' he said.

Mr Rattenbury said the rate of assaults in the jail was concerning, but said the majority of the opposition's criticisms were exaggerated, and were a distorted use of the data. He said the Alexander Maconochie Centre had experienced only one breakout attempt, which failed.

''I think that's a long way from being an insecure prison,'' he said.

He said the expenses per prisoner had dropped markedly over the past three years, and said the relatively high cost was due to the broad range of security classifications at the prison, and the large number of rehabilitation and so-called through-care programs which are designed to provide continuous treatment/support and education for prisoners from entry into prison to their post-release surroundings.

''There is a deliberate decision to work in that space, to focus on rehabilitation, and that does push the cost up,'' Mr Rattenbury said.

''I think the community would have an expectation that we are seeking to work with our detainees to ensure they don't end up back in prison again.''