An Australian doctor says medicinal cannabis could be a treatment for kids with severe autism and intellectual disabilities.

Dr Daryl Efron, has 25 years experience in paediatrics and says he believes there's a good potential high CBD cannabis will benefit children with these disorders.

The problem is the research hasn't been done - only encouraging anecdotes.

He says current medication for autism can be great, but there is a high risk of side effects.

"In adults, cannabis is being increasingly used and researched in mental health problems. We think there may be some parallel benefits in children with severe behaviour problems. We need to get on and do some good quality studies."

Dr Efron says he hopes trials can prove this, and it be one extra therapy to help these kids.