Allegations some children at Western Australia’s Banksia Hill  juvenile detention centre have been kept in solitary confinement for long periods will be investigated by the Inspector of Custodial Services.

Corrective Services Minister Fran Logan said while the department had started an investigation into the Amnesty International claims, he had also asked the inspector to conduct a separate inquiry.

“Can I assure the people of Western Australia, young people are not held in solitary confinement,” Mr Logan said on Friday.

“The only time that young people in Banksia Hill are held in separate accommodation is for protection for themselves.”

Amnesty International this week claimed some detainees had been in solitary confinement for 250 days and strip-searched, fed through a grill and constantly handcuffed when outside their cells.

The CPSU/CSA, which represents staff, immediately rejected the allegations and said the intensive support unit set up following a riot in May had provided stability.

Last year, the chief inspector revealed unprecedented levels of self-harm and other problems at the centre, recommending the state government consider repurposing the facility and opening smaller ones.