Prisoners at the Alexander Maconochie Centre will be subject to random monthly drug tests under a policy the ACT government is trialling at the jail.
ACT Corrective Services has introduced the monthly tests after it was found that the previous method of testing prisoners in large blocks over short periods of time was not providing enough intelligence on drug use at the jail.
The Canberra Liberals have now accused the government of covertly introducing a random testing policy that is similar to one that Liberal MLAs unsuccessfully proposed back in 2010.
The government has rejected the claims, saying the Liberals' proposal was defeated because it would have reduced the flexibility of the existing legislation, which already allowed for random monthly tests.
Data on drug testing at the jail, provided in response to a question on notice from opposition corrections spokesman Jeremy Hanson, shows 691 prisoners submitted to drug tests by urine analysis between December 2010 and November 2011.
Of those tests, 454 were conducted upon the prisoners' entry to the AMC, 43 as part of rehabilitation programs, and 194 were ''targeted tests'' based on information provided about a particular prisoner.
The largest number of tests was conducted in April 2011, when 109 prisoners were tested, followed by 96 in May and 81 in November.
The lowest number was in January 2011, when just one prisoner was tested.
In his response to Mr Hanson, Corrections Minister Chris Bourke said ''random tests were conducted in large blocks of tests where the majority of detainees were tested over a short period'' but this approach had significantly impacted upon the general operation of the jail.
''The executive director of ACT Corrective Services was not satisfied that this approach provided the frequency of random testing to deliver ongoing intelligence on drug use in the AMC,'' Dr Bourke said.
''She asked for a new approach to be developed.
''Monthly random testing is being trialled and draft protocols have been developed, with the goal of a full roll out in 2012-13.''
Mr Hanson said yesterday that although he welcomed the new approach, he did not understand why similar legislation proposed by the Liberals had been rejected in 2010.
The Liberals' amendment bill suggested at least 5 per cent of detainees be randomly selected by a computer each month for drug testing.
A spokesman for Dr Bourke said the Liberals' amendment bill was deemed unnecessary because the AMC chief executive could already order random testing.