New research which reveals one in four prisoners find themselves back in jail a year after release does not prove the prison service is a failure, the director general of the Irish Prison Service, Brian Purcell, has said.
However, both Fine Gael and Labour said the figures in the study published by UCD's institute of criminology yesterday underlined the failure of Irish prisons to rehabilitate criminals.
The study reveals 27 per cent of prisoners released from jail were convicted and jailed again within one year. The recidivism rate climbed to 49 per cent after four years.
However, Mr Purcell said the figures could be analysed in many ways, and did not necessarily mean the prison system was failing.
"You could look at it that way but you could also look at it and say that after a year 75 per cent of prisoners have not gone back to prison.
"After four years 50 per cent have not gone back to prison. And the reality is that the longer someone goes not coming into the prison system, the more likely it is that they would keep out of it permanently.
"So you could say that this research actually shows that in some ways prison does work. But it's a very complex area, and there's nothing straightforward about this."
It was his view that prison was not solely about rehabilitation.
"I think people need to understand that, and I think they do. The Law Reform Commission stated recently that the purpose of any sentence has to encompass rehabilitation, retribution, incapacitation and deterrent."
He believed new facilities planned for north Co Dublin and in Cork city would help create a prison system more centred on rehabilitation.
"One of the difficulties we've had in relation to issues of rehabilitation is that it's very difficult in what are essentially 19th century prison facilities to deliver a 21st century model of imprisonment. That's particularly so in relation to the range of services that we need for rehabilitation purposes."
Labour spokesman on justice Brian Howlin TD said the prison system was "simply not working". He urged greater expenditure on non-custodial alternatives.
"These figures place us at the upper end of the scale when compared with international figures, but with the system costing an average of €120,000 a year per prisoner to run - one of the most expensive in the world - these figures show that we're not getting value for money."
Fine Gael's spokesman on justice, Jim O'Keeffe TD, said the near 2,000 inmates being imprisoned every year for non-payment of fines should have their social welfare payments deducted as an alternative to imprisonment.