Juvenile justice authorities in Western Australia have been unable to verify how much time children are spending locked in their cells because of issues with a reporting system.
The prolonged confinement of detainees at Banksia Hill, the state's only youth detention centre, has been heavily criticised by advocates and legal observers.
WA's Supreme Court last year found a teenage boy had been unlawfully locked in his cell for at least 20 hours per day on 26 occasions over six months.
