Staff from the provincial auditor's office were told that the health ministry does not investigate many cases of anomalous billing because it requires too much time and effort.

But among the eyebrow-raising cases the ministry has identified are more than 500 physicians who billed OHIP for more than $1 million in 2014/15.

"The ministry suspected that some of these billings might have been inappropriate: for instance, medically unnecessary services might have been performed or payment made for services that had not been rendered, or the standard of care might have been breached in other ways," the auditor's report reads.

It cites the case of an ophthalmologist who billed $6.6 million in 2014/15 and who has previously been described by Health Minister Eric Hoskins as the province's highest billing doctor.

The majority of this ophthalmologist's billings came from performing laser procedures. The ophthalmologist performed the procedures on average seven times per patient over the year. This doctor also billed $1.4 million for diagnostic testing.

"Ordering unnecessary diagnostic tests by ophthalmologists is cited for caution by the Choosing Wisely national health campaign in the U.S. and Canada. Choosing Wisely encourages conversation between physicians and patients about unnecessary tests, treatments and procedures," reads the annual report.

The report said that since the beginning of 2013, the ministry has not proactively pursued recovering of overpayments.

Lysyk has advised the province to evaluate the costs and benefits of amending the fee-for-services billing review process and re-establishing an inspector function to oversee physician billings.

It's a controversial suggestion and one the province has said it will consider.

"There are currently strong tools in place to review and investigate discrepancies in physician billings, including routine monitoring of anomalies. However, there are opportunities to enhance these oversight measures," Hoskins said.

The province has had no inspector function since 2005 when it disbanded the Medical Review Committee.

That move was made on the recommendation of retired Supreme Court Justice Peter deCarteret Cory who reviewed the auditing process and found it to be debilitating and devastating to physicians. His review followed the suicide of a Welland pediatrician who had been audited.

OMA president elect Dr. Stephen Chris said the government already has tremendous ability to assess and audit physician practices and deal with anomalous, inappropriate billing.

He noted the existence of the Physician Payment Review Board, which is charged with adjudicating over payment disputes.

"The government has never referred anybody to it," Chris said.

"I think the government has the tools and has the desire to do whatever they can not to pay inappropriately, which we wouldn't have any trouble with," he added, charging that the health ministry is bureaucracy heavy.

There is no suggestion outliers are working inappropriately, Chris said.

"We don't have an in-depth understanding of how these individuals are working. That is information that is not available, but if the government hasn't acted on it, there must be some explanation," he said, adding that it's possible some communities require an intense level of specialty services.

Lysyk questioned why taxpayers are footing so much of the bill for physician medical liability insurance via the Canadian Medical Protective Association. The province has more than doubled its payments for this insurance over the last three years, forking out $329 million this year, up from $145 million in 2013.

The auditor also found problems with a patient-enrolment payment model adopted by the province about a decade ago. Last year, it cost $522 million more than it would have under the traditional fee-for-service model. That's in part because 1.8 million patients enrolled in these group practices did not see their physicians during the year, yet the doctors were paid $243 million for having them enrolled.