Corrections Act 2004, s 124; Prison Operations Manual, S.07.01.04
You can be tested any time the prison staff have reasonable grounds to suspect that you’ve used drugs or alcohol – for example, if a prison officer smells drugs in an area and you’re within that area, or if the prison have been given information that you’re using drugs or alcohol. The grounds for suspicion must be stated in a written incident report. A test should take place within seven days after the suspicion arises.
You can also be tested randomly (see above). Approximately one in 10 prisoners are tested randomly each month for general random testing. About one in five IDU prisoners or prisoners on temporary release are tested each month.
There’s no limit on how often you can be tested during your sentence.