The future of Ireland's Drug Treatment Court is in doubt after new figures revealed that just four people a year successfully qualify from the programme.
The court, which was established in 2001, offers addicts an alternative process which allows them avoid prison in return for participation in a strict rehabilitation programme.
After the low success rate, the Department of Justice has signalled it is time to "go back to the drawing board".
It has expressed concerns about the future of the programme and is awaiting a complete review due in the coming weeks.
Proponents of the system have defended it saying the course is difficult to qualify from. But figures released by the Courts Service of Ireland (CSI) show a low success rate.
A total of 374 cases were referred to the court since 2001, of which just over half (53%) have been accepted as suitable candidates.
Of these 200, just 32 (16%) have successfully completed a programme that includes detox, education, counselling and general support. Four of those 32 have "returned to their former ways of reoffending".
Addressing a Public Accounts Committee (PAC) late last year, Sean Aylward, the secretary general of the Department of Justice said he was "disappointed with the court's low output and am not convinced any longer that is the way we should go".
"While it was started with the best of intentions, the production level of the court does not justify extending the model elsewhere. It is not working and we must go back to the drawing board."
Although the court has seven members on its team including a district court judge, a garda, a coordinator, a probation and welfare officer, a nurse and an education officer, the CSI insists the duties are subsumed into their regular work and pose no additional cost.
Instead, an examination of the court has been applied more to its practice and effectiveness than to its value for money.
To qualify for the programme, applicants must be from Dublin's north inner-city or from the Dublin 7 area, be over 17 years of age, willing to give up drugs and have pleaded guilty to district court level offences likely to lead to a prison term. Drug addicts who are repeat offenders stand a much higher chance of receiving custodial sentences.
The programme lasts up to 18 months but it takes around 10 weeks to establish suitability beforehand.
For those who are successful, outstanding criminal charges will be struck out of court on the condition they remain out of trouble for 12 months.
Those in favour of its continuation argue that despite the low success rate, the programme leads to a decrease in criminal behaviour by participants, including those who are considered but eventually deemed unsuitable. It also reduces garda costs and legal aid costs as there is no constant representation.
But concerns remain. Addressing a Dáil debate last November, John Curran, Minister of State at the Department of Justice, said: "There are significant questions over the Dublin Drug Treatment Court relating to the throughput and graduation levels which have not become close to achieving what was intended on the establishment of the programme."
While 100 participants were anticipated in the first year, 37 were deemed suitable to participate and there were just four qualifications between 2001 and 2002.