Autism Asperger ACT manager Susanne Morton said while it was wrong and inappropriate to put a child in a cage, the school might well have thought it was doing the right thing.
"Schools are trying with limited resources and obviously they're getting it wrong sometimes," she said. "Generally I'd say to be cautious and know everything about the case because we have a lot of contact with the schools and they try really hard."
Children with autism often needed a safe place and her organisation worked in schools to set up a "sensory corner" or a chair where they could take time away, she said.
"The fact that they've used fencing might make it seem it was more sinister than what was the intent – it doesn't sound appropriate, it sounds a bit scary," Ms Morton said, but she expected the family would have known about the structure from taking their child to and from school.
Schools were under-resourced and teachers not adequately trained to deal with autism, with one in every 80 children now diagnosed with the condition, she said.
"We are hearing about incidents of restrictive practices more frequently, including restraints and seclusion," Ms Gotlib said. "It is increasing and it's a clear reflection of a system which is inadequate in meeting the needs of students with a disability. Teachers are stretched to the max. Some of them don't have appropriate training. The system is in crisis."
Children had been locked in "time out" rooms or physically restrained.
"It is a form of abuse. Would teachers physically restrain a child without a disability?" Ms Gotlib asked.