Though Liberal Leader Dalton McGuinty won't commit to clearing a queue for autistic children awaiting treatment, he admits more should be done for them.

McGuinty was speaking at an elementary school in Brampton north of Toronto on Friday when he made the remarks, saying "more work needs to be done."

However, he wouldn't provide details on what that work might include or what immediate steps the government could take.

The opposition parties have slammed the Liberal Party's handling of the autism issue, saying the number of children waiting for the treatment method known as IBI (intense behavioural intervention) has increased dramatically under McGuinty's government.

Conservative Leader John Tory is among those criticizing McGuinty on the issue. On Friday, Tory accused McGuinty of outright cruelty, saying he promised in writing during the last election to help autistic children, but has broken his word.

"They thought they had a champion; what they received was a champion promise-breaker," Tory said.

"I consider this kind of behaviour not just unaccountable, not just irresponsible, but quite frankly, it's cruel."

The Liberals maintain that spending on autism has almost tripled under their watch, and the number of children accessing IBI programs has more than doubled.

Tory contradicted that position, saying the government has actually been fighting in court for the past several years to limit funding to children with autism.

Tory says he would spend $75 million to provide the necessary resources to the children, and another $5 million to allow parents some relief from caring for their autistic kids.

During McGuinty's Friday visit to the school in Markham north of Toronto he unveiled a new plank in the party's education plan. If re-elected, McGuinty said, he would spend up to $150 million annually to reduce class sizes in grades 4 to 8, boost arts programs and help students get ready for high school.