TORONTO - The NDP are warning Ontario parents that the new harmonized sales tax may be applied to a crucial but costly therapy for autistic kids.

NDP Leader Andrea Horwath is demanding that the government come clean about whether it will apply the tax on IBI therapy for children.

She says the government is anticipating that the HST will apply in some cases.

Horwath says it may be not apply if the psychologist providing the therapy is exempt and included in a national registry of psychologists.

But the government removed that requirement for patients who want to obtain IBI for their kids.

Horwath says the HST move rubs salt in the wound for parents who are already dealing with long wait lists for the treatment.