TORONTO -- Public health advocates say many private clinics in Ontario are misleading patients and unlawfully billing them for medically unnecessary services.

The Ontario Health Coalition says a significant number of clinics they contacted were charging patients extra fees on top of billing the Ontario Health Insurance Plan for necessary procedures.

It says one clinic was charging patients $50 "administrative fees" for such things as a snack and patient records.

The group says such fees were more common among cataract clinics, which were charging patients for medically unnecessary tests and procedures when they came in for needed surgery.

They say clinics are manipulating patients, who are confused about what they need and what they don't need.

The coalition says the government must crack down on such user charges which are more widespread than ever.

Health Minister Deb Matthews says she'll look into any unethical practices to protect Ontario's single-tier public health-care system.

She says patients can call the government if they're being charged for services covered by OHIP.