Labour has said it will introduce alternatives to imprisonment for many non-violent offenders if returned to Government.
The party has proposed that District Court judges would be obliged to consider all alternatives before imprisoning someone, and give a brief written explanation of any custodial sentence.
It also proposes, in a new document on penal policy, an increase in the number of Juvenile Liaison Officers and more resources for the probation and welfare services.
It says the continuing use of St Patrick's Institution for the imprisonment of children is a clear violation of Ireland's human rights obligations and should cease immediately.
The document also calls for the implementation of the Inspector of Prisons' 2009 recommendation that no more than 540 prisoners be accommodated at any one time in Mountjoy Prison.
"No-one could describe our present system as effective," says Labour's justice spokesman Pat Rabbitte. "Even if you leave to one side the cost in human terms it is clear that we cannot afford to commit ourselves to this ever-increasing outlay of scarce resources into a system that has little or no impact on re-offending rates."
Other proposals include the appointment of a Prisoner Ombudsman, a move to smaller and more local prisons and more places in open prisons. If Thornton Hall is to go ahead, consideration should be given to remodelling at least part of the complex in north Dublin along open prison principles.
Labour says the Government's penal policies are not working. The prison service is overwhelmed and in crisis. Chronic overcrowding, rising violence and demeaning physical conditions are making criminality worse rather than addressing it. The prison population is growing by 10 per cent a year and the system is one of the most expensive in the world.
The party says imprisonment should be a last resort and more effective and appropriate alternatives should be used where available. This principle would be specified in a new Sentencing Act to provide guidelines for judges and ensure greater consistency between cases.