The boys have been housed in Banksia Hill's Intensive Support Unit (ISU), which, according to the Department of Justice, provides targeted care for children and young people assessed with complex needs and intervention as a result of being at risk of harm to themselves or others. In a letter obtained by WAtoday, one of the boys wrote of his desperation. "I do not understand why I have been in ISU for so long," he wrote. "I have been trying to cope with my anger. "I'm not the type of person to talk about my problems.

"The first couple of months was the hardest for me because I wasn't really getting any time out of cell and was lucky if I got an hour out of cell a day." The boy said he was seeking legal help, and that his stay at Banksia had been the hardest thing in his life. "I strongly think that ISU has changed me in a bad way," he said. "I'm more institutionalised ... and just feel very cold hearted. "The reason I am writing this letter is because I really do feel like this is the last straw for me.

"I need help and I need it fast or I will end up doing something stupid." Another boy said he had been threatened by a guard and told he had two options left; one was a coffin, the other was being "bent over" in an adult prison. The boy claimed to have been "locked in isolation" and said the pain of self-harming was better than the pain of ISU. The Department said detainees in ISU were not isolated, but a spokesperson for Amnesty International said "several sources" claimed the boys had been held in solitary confinement for "at least two weeks at a time between May and August last year". Amnesty's Indigenous Rights Manager, Tammy Solonec, said she had been deeply disturbed by the detainees' version of events, which included being held for "weeks on end" in a cell as small as a car parking space, with as little as 10 minutes out of the cell each day.

"It is critical that the West Australian government instigate a full and thorough investigation into the situation for these two boys, and into the operations of the Intensive Support Unit," Ms Solonec said. "Pending that it must be closed immediately. "Amnesty International is aware that plans now exist for integration for both these detainees, however the fact remains that it is not appropriate for children to be held in facilities that do not meet international standards." Ms Solonec referred to the boys' allegations of severe mistreatment as the latest in an "avalanche of horrors" spilling out from Banksia Hill in the past six months. RELATED: WA government refuses to close juvenile jail despite damning report

Corrective Services Minister Fran Logan acknowledged he had received correspondence from Amnesty International regarding a detainee at Banksia Hill, and while he could not comment on an individual's case, he said the centre had undergone a "significant transformation". "The issues raised by the Inspector of Custodial Services about the operation of Banksia Hill under the previous Liberal-National government in 2016 are being addressed," he told WAtoday. "The facility has stabilised considerably compared to where it was." Mr Logan said previous rehabilitation and education programs had been affected by instability caused by a poorly implemented management model, but a new model of care was being finalised and programs were now "running as they should". A Department of Justice spokesperson said operations at Banksia Hill Detention Centre were subject to ongoing oversight by the Office of the Inspector of Custodial Services and the Independent Visitor Service.

"Placement of any young person in the ISU comes with significant oversight," they said. "This includes ongoing assessment of the need for the young person's placement and reporting." Amnesty International said no formal response had yet been received from the minister with regard to the boys' allegations, but a spokesperson said she understood the Department was looking into the individual claims. Mr Logan said he would respond to Amnesty International "soon".