Juveniles being detained at an adult prison in Perth should be released on bail with strict conditions until their usual facility is fixed, a top barrister says.

About 150 juvenile offenders are being housed in the high-security Hakea remand facility following a riot at the nearby Banksia Hill juvenile detention centre in January that left dozens of cells trashed.

Three separate inquiries are being held into the riot, which involved only a handful of inmates.

The list of repairs needed will not be finalised until the inquiries are complete, and there are concerns the juveniles could remain at Hakea for more than a year.

One of the inquiries has heard claims the teenagers are being abused by officers, denied visits, and were losing weight because of a lack of food.