Up to 15 prison inmates are being moved from Albany Regional Prison following an incident at the facility on Thursday night.
The Department of Corrective Services spokeswoman confirmed the incident started at 6pm on Thursday, when 20 prisoners barricaded themselves in a unit, causing damage to the unit and its yard.
Commissioner James McMahon said the incident was sparked by a few “ringleaders” and the prisoners surrendered themselves to officers and all prisoners were cleared from the unit by 2.20am.
He said most of the prisoners involved were transferred out of Albany Regional Prison to be accommodated separately in other facilities.
The prisoners were transported to Perth by the Department of Corrective Service's Emergency Support Group, the spokeswoman said.
Mr McMahon said the department was still assessing the damage, which was not believed to be extensive, and no prisoners or staff were injured.
However, WA Prison Officers Union secretary John Welch tweeted just after 10am on Friday that a "very serious incident" had caused "very significant damage" to the prison.
Corrections Minister Joe Francis said he was told there was a "contained disturbance" and he was attempting to find out more information, including the cause and the extend of the damage.
He added that he was thankful there were no injuries to staff, prisoners or the general community.
Mr Welch said the incident would contribute significantly to prison overcrowding in Perth and a unit, temporarily closed for renovations more than two years ago, had not been re-opened.
He said that WA Corrective Services staff were forced to transport the prisoners to Perth because Serco staff were on public holidays.
"This incident just goes to prove how dangerous it is to be a WA Corrective Services staff member, with the extra stress and pressure put on them by incidents such as this," he said.
"In the context of overcrowding the loss of these cells is extremely significant.
"There are currently 5140 prisoners in the WA prison system, and most prisons suffer from chronic overcrowding."
Serco spokesman Tim Evans said the contractor was available to transport the prisoners.
"Serco are operating all required and requested transports, hospital sits and movements in accordance with our contract," he said.
"Any statement that Serco are not undertaking prisoner transports today because of a public holiday is false and misleading."
A Department of Corrective Services statement said it was "normal practice" for the Department's Emergency Support Group to transport prisoners if necessary.
