OTTAWA - Unlicensed doctors, nurses and other medical staff may be treating sick and injured Canadian soldiers, sailors, aircrew members and their families, the auditor general warned Tuesday.

Sheila Fraser's latest report says the military has failed to keep track of whether its health-care staff have maintained their licences and certifications following enlistment.

Fraser said at a minimum the Defence Department should know the professional status of each of its 2,275 regular force health staff.

"All regulated professionals, both military and civilian, are licenced and certified before they are hired by the department,'' said the report to Parliament.

"However the department does not monitor its military health-care practitioners once employed to ensure they maintain their licences or certifications and are in good standing with a regulatory body.''

Since they do not keep track, Fraser said defence officials conceded "they do not know if unlicenced practitioners are currently providing direct patient care.''

The Defence Department estimated in 2006 as many as 20 per cent of its military health-care providers may not have been licenced.

Fraser's report also raised concerns about the billing practices of civilian doctors who work on contract for the Defence Department. There were some cases where it appeared doctors were paid for work at clinics that were closed and other examples of double-billing for hours.

Fraser said that the matter has been referred to the department's internal auditors.

The opposition Liberals attacked the Conservatives in the Commons on Tuesday over the absence of certification checks.

"This is a government that doesn't seem to take the health and well-being of our soldiers seriously,'' said defence critic Denis Coderre.

But a spokesman for Defence Minister Peter MacKay says the department is looking into both the question of possible extra billing and the certification of doctors.

''We are asking for a list of options on how to better manage the issue -- we know they were all certified when they began, now we want to make sure there is a system in place that monitors certification,'' said Dan Dugas in an e-mail note.

In the course of her audit, Fraser's staff tried to do their own their own survey, asking military doctors to show proof of their licences. Of those who responded, 69 per cent were able to show they were registered with a provincial college of physicians and surgeons.

"National Defence does not have some of the basic information we would expect to see in a well-managed system of heath care,'' said Fraser.

Aside from licencing, she also suggested military medical staff are not keeping up with the latest developments in the rapidly evolving health-care field.

Few health professionals take advantage of skills maintenance courses because "they believe they cannot be spared from regular duties,'' said the report.

In responding to the complaints, defence bureaucrats said they currently maintain a database that keeps track of the credentials of dentists and pharmacists. That central registry will be expanded to include doctors, nurses and technicians.

The report also raised concern about the training for physician assistants, who often substitute for doctors on warships deployed overseas.

In 2002, a standard of training was introduced that required the military's 124 physician assistants to become certified. Fewer than half of them have taken the course and only 20 per cent are actually certified five years later.

"As a result, a large portion of the physician assistants in the military medical system are provided patient care without having been certified or, in some cases, without having passed the new standards,'' said the report.

Questions about the training and ability of physician assistants were raised after a 2004 fire aboard the submarine HMCS Chicoutimi, which left one sailor dead. More than half a dozen sailors suffering smoke inhalation had to be treated by the lone physician assistant on board.

Despite the concerns, a survey found that most of the military's 65,000 members and their families are satisfied with the care they received at 37 facilities across the country.

National Defence spends about $500 million a year on health-care benefits, but Fraser said the cost is rising substantially, partly because of the war in Afghanistan. Last year the military spent $8,600 per member on health benefits, almost double the Canadian average.