A mother is demanding an apology from a Sydney hospital over the mistreatment and misdiagnosis of her autistic 9-year-old son.

A Canberra child psychologist has warned cuts to support for special needs students could force children to leave schools. 

And the $100-million federal savings have already had some parents in tears, when early intervention pre-schools were abolished, Dr Eryn Davies said.  

"If they keep cutting funding, for the schools and mental health as a whole, it's going to be a point where it would just be a mess," she said.

"They're going to have to completely push back in funding because people in this situation just won't function," she said. 

Nicky Phillips Science Editor

A study has found children with autism face up to a 4-year delay in their diagnosis. Photo: Supplied

By Sacha Payne

Disability advocates say revelations of a cage built for an autistic child at a Canberra school are just the tip of the iceberg.

The Principal of the school, which cannot be named due to privacy reasons, has been stood down as an investigation is launched.

The cage at the Canberra school was exposed following a complaint to the Australian Human Rights Commission.

Images obtained by SBS show what some schools use as so-called withdrawal areas for autistic children.

In the wake of revelations an autistic Canberra student was confined in a cage-like structure, former disability discrimination commissioner Graeme Innes says such abuses are widespread and has called for a broad inquiry into the treatment of children with disabilities in the nation's schools.

Opposition Leader Bill Shorten immediately backed Mr Innes' call, declaring: "we cannot assume this is a one off case".

Mr Innes, who served as the nation's disability discrimination commissioner from 2005 until last year, said such "appalling" incidents were not confined to the ACT.

Kirsten Lawson Chief Assembly reporter for The Canberra Times.

News of a cage-like structure being used to constrain a Canberra school child has come as no surprise to some parents, who say their children have also been poorly treated by the system.

The ACT government has confirmed the cage structure built to contain an autistic Canberra school student had a roof, as shock and distress at the behaviour control technique spread nationwide.

Canberra Raiders coach Ricky Stuart - a prominent autism awareness advocate - joined a chorus of disbelief after Thursday's revelation a primary school had used a 2m by 2m structure made of pool fencing as a "withdrawal space" for a 10-year-old boy.