Chronic staff shortages are also contributing to the problems at Casuarina Prison, where concerns have been raised about the facility's ability to rehabilitate inmates for re-entry into the community.
Custodial Services Inspector Eamon Ryan noted WA's largest publicly run prison was being redeveloped, and is set to become the biggest in Australia with a capacity for more than 1800 inmates.
"The question has to be asked: how big is too big?" he said on Monday when his inspection report into the facility was tabled in state parliament.
Mr Ryan said the expansion would bring complications "associated with managing so many people and their needs".
A high-security unit is under construction and there are plans for a forensic mental health unit, an expanded infirmary and a high-dependency unit.
These will be in addition to the current mainstream units, special protection unit and the alcohol and other drugs rehabilitation unit.
"Safely managing prisoners with so many diverse needs, conflicts and risks between them is a considerable challenge," Mr Ryan said.
He said many prisoners had mental and other health needs, as well as intellectual and cognitive impairments.
"The situation is exacerbated by the lack of meaningful and constructive activity in the daily regime, with high unemployment and underemployment," he said.
Mr Ryan said the prison's infrastructure and resources were not able to cope with the current number of inmates who were not being provided with meaningful activities like industries, recreation and education.
This was found to be undermining safety and security at the facility and its ability to rehabilitate inmates and prepare them to re-enter the community.
Chronic custodial staffing shortages driven by unplanned absences, like personal and workers' compensation leave, are an aggravating factor, with some officers saying it was also causing low morale.
Casuarina Prison is located 37km south of Perth's CBD.
12°C