Last week, the Department of Justice ordered a three-day search of Bunbury Regional Prison after drugs and drug paraphernalia were located on the premises.
According to WA Corrective Services Commissioner Tony Hassall, prison staff uncovered various items in the metal workshop area on Saturday, November 2.
The staff found a crystalline substance, leaf material, an unknown fluid, and syringes/needles inside a metal pipe and metal tubing.
The ensuing search involved Special Operations Group, Drug Detection Unit, Corrective Services Academy, Bunbury Regional Prison, and Albany Regional Prison personnel as well as canine assets.
The department's Professional Standards Division also assisted with enquiries.
Mr Hassall said the department was working around the clock to stamp out drug offences within the state's prison system.
"The decision [to hold a three-day search] was part of the department's commitment to have a zero tolerance approach to drugs in our prisons," he said.
"I won't take any risks regarding staff, prisoner, and public safety. We will continue to carry out intelligence-led searches and random searches.
"We will apply rigorous sanctions to anybody caught bringing drugs into our prisons."
Mr Hassall said the staff and the department were committed to running a safe, secure prison.
"The staff are pleased we're not compromising their safety or the prisoners' safety," he said.
"We're committed to stopping the supply of drugs into our prisons."
WA Police and the Department of Justice are set to continue their investigations into the matter.