B.C. Health Minister Adrian Dix has asked officials to examine whether the ministry’s disciplinary process can be accelerated, saying he is concerned about how long it took to reprimand one of the province’s highest-earning doctors for overbilling.

On Tuesday, a Globe and Mail investigation revealed that provincial auditors began scrutinizing Winston Tuck Loke Tam’s billing practices in 2010, but it took almost six years to conclude the entire process and order the obstetrician-gynecologist to give back $2.1-million − one of the highest repayment rulings ever issued to a health practitioner in Canada.

Open this photo in gallery Dr. Winston Tuck Loke Tam. handout/The Globe and Mail

Over much of that time, Dr. Tam kept collecting millions more in public dollars (he was B.C.'s top billing obstetrician-gynecologist for 13 years). And patient concerns about his clinical care also kept mounting, triggering separate investigations, including one by the College of Physicians and Surgeons of British Columbia, which regulates the practice of medicine in the province.

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“We have rule of law. People are innocent until proven guilty. They have legal assistance and it’s always going to take time," Mr. Dix said in an interview on Wednesday. “But at the same time, clearly it took too long,” the Health Minister added. “I think there are lessons to be learned from this, absolutely.”

Mr. Dix declined to weigh in on whether the physicians college should have pursued its own disciplinary action against Dr. Tam, who resigned his practice in April, 2015.

“I’m not going to second-guess the college,” he said. "They have a public duty to take action in these cases and I know they take that very seriously.”

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As part of its investigation, The Globe communicated with nearly 40 former patients who alleged some form of mistreatment by Dr. Tam, who ran a clinic in Surrey, B.C., and also worked at Surrey Memorial Hospital. The women allege that Dr. Tam performed medical procedures such as vaginal exams without their consent and made disparaging remarks about their bodies, weight and sex life. They also accuse him of botching the births of their babies, performing unnecessary C-sections and failing to do basic tests, such as urine analysis and pelvic exams.

More former patients have contacted The Globe with concerns about Dr. Tam since the newspaper’s investigation was published. One patient, however, e-mailed to express support for the doctor, saying she found him to be “always communicative, caring and gentle.”

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The college reiterated that it could not comment on Dr. Tam’s case because of privacy rules. Patient complaints against doctors are not made public unless an internal investigation leads to disciplinary action, a spokesperson for the college said. “Complaints are allegations until they have been proven,” the spokesperson added.

By the time the $2.1-million repayment order was issued to Dr. Tam by the province in May, 2016, he had already left Canada to work at a hospital in China. He was employed at the Shanghai United Family Hospital for nearly a year. The Globe could not establish his current whereabouts.

Experts say increased oversight of medical billings in Canada is needed to detect and prevent financial abuses in the health-care system. Joel Alleyne, who helped found the Global Health Care Anti-fraud Network, said overbilling is an issue across the country, noting that provinces have audit systems in varying stages of maturity.

“There is a certain amount of overbilling in the system today that taxpayers are losing out on,” Mr. Alleyne said. He added that Canada lags behind the United States and other jurisdictions in cracking down on financial abuses in health care.

Joan Brockman, a criminology professor at Simon Fraser University who has studied health-care fraud, said the largely trust-based billing system creates opportunities for abuse. “It’s the perfect opportunity set up for people to defraud.”

It is not known if Dr. Tam has paid the $2.1-million that he owes the province for improperly billed medical services, interest and the cost of his hearing. The B.C. government declined to disclose this information, citing the doctor’s privacy rights.

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Information obtained by The Globe through a Freedom of Information request reveals that $7.7-million in improper billings by B.C. health practitioners have gone unpaid. The sum is approximately one third of the total amount requested for repayment by the provincial government over the past five years.

Dr. Tam worked in British Columbia for 14 years, billing the province a total of $19.3-million. The final decision in the audit of his financial practices concluded that his books were rife with errors and that he had a “propensity to cut corners while maximizing his billings.”

With reports from Renata D’Aliesio