Head of the Early Childhood Council Peter Reynolds has delivered a blistering attack on the Education Ministry's lack of support for under 5s with special needs.
He told the Education and Science Select Committee inquiry into support for children with autism and dyslexia that thousands of children could be suffering developmental delays because they were not getting enough help.
He said children were waiting too long to be assessed and when they were diagnosed, the amount of specialist help they got was insufficient.
"The problem's right throughout the system, it is a complete failure, unfortunately we've got parents and we've got educators and we've got children who are having to fight for every possible scrap of support they can get."
He said a survey of its members' early childhood services found 80 percent had children who were not getting enough help for their special needs.
Mr Reynolds said that indicated there could be thousands of children who were missing out.
The survey also found children have been punched and kicked and teachers admitted to accident and emergency departments because of a lack of support for children with disabilities.