Autistic disorders are often diagnosed in childhood
Politicians are being urged to recognise the need for legislation to protect the rights of the 20,000 people affected by autism in Northern Ireland.
A rally will be held at Stormont later promoting Autism Awareness Day on Thursday.
On Tuesday, the Assembly is expected to debate the condition.
The chief Executive of Autism NI, Arlene Cassidy, said existing legislation did "not allow for autism" and did "not recognise autism".
"Parents are having difficulties in accessing benefits such as disability living allowance for example," she said.
"They are having problems in accessing social opportunities that would be open to other groups because there is a lack of awareness."