Special operations group officers were called to Hakea Prison late on Wednesday when seven out-of-control inmates trashed part of a wing and made threats against staff.
No injuries have been reported and the Department of Justice will review the incident.
Secretary of the WA Prison Officers Union, John Welch, says the incident highlights the urgent need for the state government to fix “chronic overcrowding” in WA prisons.
Mr Welch said Hakea was about 300 prisoners above design capacity, with the majority of inmates double-bunked.
He said a new prison was desperately needed as WA’s adult prison population rapidly increased from 4964 to 6776 over the past five years, according to Department of Justice statistics.
“We understand and are sympathetic to (the government’s) financial plight but our members deserve to be working in a safe environment,” Mr Welch said.
The number of prisoners on remand has also skyrocketed, up from 1754 to 2002 in the past year.
Corrective Services Minister Fran Logan congratulated prison staff for handling the incident quickly and with minimal damage.
Damaged cells will be up and running tomorrow, a Department of Justice spokesperson said.