"It was clear that the use of isolation was routinely and frequently used, and for very long periods of time, and that was confirmed by some of the young people," she said.
"And when I say frequently and routinely … it's 23 hours a day for several weeks that some young people, and in high security, in the maximum security area, that was of absolute concern."
She said detainees told her they felt “angry, depressed, sad, and like caged animals".
"If you go to that maximum security area you will understand why they feel like that," Ms Mitchell said.
“The facility itself is old and ageing, and things are broken and toilets are rusty … There’s no air-conditioning. It’s very hot. There’s minimal air flow and there are periods of extensive isolation and use of force. And I think all these things are breaches of human rights”, she argues.
What is needed in detention centres?
National Children's Commissioner Megan Mitchell believes detention centres must ensure they have:
• External independent complaint mechanisms
• Oversight of those administering detention centres
• Highly trained and well recruited staff
• Detainee access to family on a regular basis
• Detainee access to legal remedies and advice
• Adequate education and activities for detainees