A leading disability advocacy group has demanded the resignation of the chief executive of the country's largest autism service provider in the wake of a series of allegations about mistreatment of children in its care.

The call for Autism Spectrum Australia (Aspect) chief executive Adrian Ford to resign comes as state and territory ministers fail to agree on proposed safety and quality measures under the National Disability Insurance Scheme.

The chief executive of Autism Awareness Australia, Nicole Rogerson, said the allegations about two Aspect schools in NSW and Victoria were "distressing".

In one case a boy was allegedly left in a cage-like structure at Aspect Macarthur School in Sydney's west while another Aspect school in Melbourne allegedly used a lockable box to restrain students.