Ms Lewsley said she was aware, through casework and meeting children and their parents, that too many young people were faced with too many issues because of having a condition on the autistic spectrum of disorders.
“For too long services to children and young people with autism and associated disorders have been patchy and not delivered well,” she said.
“While there is some good practice, children and young people are facing a postcode lottery in terms of accessing good services on a consistent basis.
“The establishment of a cross-party group will bring this issue to the heart of the Assembly and hopefully make sure that changes can be made.”
The Commissioner said research carried out by her office had shown the difficulties faced by children with autistic spectrum disorders in education and health services.
“I back any group or organisation which is trying to promote and safeguard the rights and best interests of children and young people, whether it is through legislative change or campaigning for better services.
“Legislation in itself will not make things better. There are already laws on the statute books not being implemented.
“What we need is the willingness to make sure that the needs of every child with an autistic spectrum disorder or any special need receives the support and services they need.”