CANNABIS and a prescription drug with euphoric effects are South Australian prisoners’ drugs of choice, figures reveal.

SA prisons drug-test information, obtained under the Freedom of Information Act, shows that in the last financial year, 839 prisoners — about one in five of the prison population — returned a positive drug test.

The most common drug used was cannabis, with 430 prisoners testing positive, while 305 found to have used buprenorphine, a prescription drug usually used to treat heroin and other opioid addiction or for pain relief.

Amphetamines, such as crystal meth and ecstasy, were the next most used with 73 positive tests.

There were just more than 50 positive tests each for methadone, benzodiazepines including Valium and Xanax, and antidepressants.

There were almost 150 drug tests where a prisoner tested positive to more than one drug.

Cadell Training Centre and the Adelaide Women’s Prison returned the highest proportion of positive drug tests in proportion to the number of prisoners.

A Corrections Department spokesman said most drug tests were either targeted based on suspicion, following a request from the Parole Board or part of a prisoner’s contract when they move from a cellblock to low-security, cottage-style accommodation.

The spokesman said at the Cadell Training Centre and Adelaide Women’s Prison inmates could earn privileges by showing compliant behaviour and remaining drug free.

“In order to participate in (workshops or supervised community work) ... or to make the transition from cellblock accommodation to cottage style accommodation, prisoners are subject to regular drug testing,” the spokesman said.

A Drug and Alcohol Services SA spokeswoman said the illicit use of prescription opioids (such as buprenorphine) was an issue in Australia.

Opposition correctional services spokesman Dan van Holst Pellekaan, who obtained the figures, said the consistently high level of drug taking by prisoners highlights another government failure.

“The positive test results alarmingly reveal that inmates at Adelaide Women’s Prison with a 148-bed capacity returned 124 positive drug tests and the Adelaide Remand Centre with a 267-bed capacity returned 183 positive tests,” he said.

“In response to the number of positive drug tests in 2011-12 the Minister claimed that it was targeted testing which was leading to the high number of positive results.

“If that were truly the case then the level of drug taking should have reduced over time.

But, instead, we are seeing the figures increase and the Government losing this battle.”

Network of Drug and Alcohol Service executive officer Andris Banders said SA prisons needed to offer more drug rehabilitation programs to break offenders’ addictions.