Staff at the Banksia Hill Juvenile Detention Centre in Perth warn they are enduring constant violence sparked by detainees being locked down for days at a time, saying some of them should be moved to an adult prison to improve conditions.

In a letter to WA's Acting Commissioner of Corrective Services, Mike Reynolds, they recommended a portion of the centre's juveniles be immediately moved to an adult prison to improve conditions for both staff and the detainees.

The letter said because of increased workloads and severe understaffing, on some days there were nine or more lockdowns in each unit, "with an ever-increasing risk to staff as detainees refuse to return to cell".

Staff said there had been an "extreme increase" in the level of self-harm and suicidal ideation, saying it had resulted in one detainee needing CPR and being revived on two separate occasions.

"Staff daily are enduring constant abuse and assaults from a cohort of detainees who are frustrated and angry due to lockdowns that sometimes last for several days at a time," the letter said.