The colourful building toy Lego has been used by therapists for nearly 20 years as a treatment tool for children diagnosed with an autism spectrum disorder.

It started when neuropsychologist Daniel LeGoff noticed how normally introverted children with autism would interact and socialise with peers while playing with Lego.

Informal and NDIS-supported autism lego groups are now emerging around Australia, with parents saying the sessions are often the only time their child communicates with others.

This informal social lego for the autism group is held weekly in Mackay, north Queensland. Most of its members are children have been diagnosed with ASD.

Parents of group members say the lego group has given their children confidence and social skills and has helped with schoolwork and hand-eye coordination.