An Ontario doctor could have his licence revoked for a second time for allegedly sexually abusing a patient four months after his licence was reinstated following other sexual allegations.

Monday will mark the third time Dr. David Stuart Lambert has appeared before the Ontario medical college's disciplinary committee. In 1991, his licence was suspended for six months after the College of Physicians and Surgeons of Ontario found he made "a series of derogatory and demeaning comments of a sexual nature to patients."

Then in 2002, his licence was revoked after the college found Lambert sexually abused one female patient, made sexual remarks to two others and acted unprofessionally with another by trying to sell her skin care products.

The college decided in June 2009 to reinstate Lambert's licence, albeit with very strict conditions. He was only allowed to treat adult male patients, had to see a therapist, practise under supervision and refrain from selling skin care products.

Four months after Lambert's licence was reinstated, the college sent two private investigators to Lambert's clinic, ostensibly to receive a cosmetic medical procedure, according to allegations from the college.

He sexually abused one of them by touching her breast, the college alleges. One of his patients has also come forward to allege Lambert tried to sell skin care products.

Hearings into the allegations that Lambert breached the terms of his reinstated licence by treating female patients and trying to sell products are scheduled for several days this week and one week in August.

After the latest allegations came to light, the college suspended Lambert's licence pending the outcome of the hearings, but the college alleges Lambert has continued to practise medicine.

A call to request comment from Lambert's lawyer was not returned.