Parents and schools are at loggerheads over how to handle increasing numbers of children with "incredibly difficult" problems moving into mainstream classrooms, a world-leading expert in child behaviour disorders has warned.

Professor Mark Dadds said legal and ethical concerns left teachers hesitant about discipline at school, but sending children home on suspension risked encouraging the behaviour. "I think this is coming to a head and it needs to be thought through very carefully," he said.

"It's feeding into this terrible blame game that seems to be growing in Australia, where schools are saying that the children are to blame, and the parents are increasingly saying the school is not managing the child right."

Experts are concerned about an escalating blame game between teachers and parents about in-school discipline. Credit:Michele Mossop

Last year more than 600 NSW kindergarten students were suspended from public schools alone. Almost 150 of them received long suspensions of between five and 20 days for physical violence or persistent or serious misbehaviour.