An Alberta Liberal MLA is calling for an investigation following a string of departures from the Calgary medical examiner's office.

"Clearly there are problems in the chief medical examiner's office in Calgary. This is costing us in terms of quality of investigations and deaths. It's also costing us financially," Liberal MLA David Swann said Sunday.

"There needs to be somebody going to that office and interview all the staff and find out what's going on. What is the problem here when 80 per cent of these specialists are leaving?"

Ina Lucila, a spokesperson for Alberta Justice, confirmed in a statement to CBC that four of Calgary's five medical examiners have resigned. Two are scheduled to leave this spring, one in summer and one in late summer or early fall.

Replacements have been found for three of the four departing physicians, and the department said it has arrangements in place to bring in temporary doctors and Edmonton-based medical examiners to help with the transition. Five of the province's medical examiners are in Calgary, and five in Edmonton.

Offices are 'fully taxed' with opioid crisis

Swann said both offices are "fully taxed" due to the number of deaths in the province, particularly deaths relating to opioids.

"This means that families of loved ones who have died from an opiate or drug overdose or unknown causes are having to wait over a year to find out information. That's not acceptable," Swann said.

"It's anybody's guess what's going on there ... it's up to the justice minister to find out."

As of 2017, there were 50 forensic pathologists practicing across Canada. Swann said the specialists are in very short supply across Canada as the role requires at least an extra five years of training on top of a medical degree.

Four of Calgary's five medical examiners have resigned. (Anis Heydari/CBC)

In December 2016, Dr. Elizabeth Brooks-Lim was named Alberta's chief medical examiner after serving in the position for just five months following the departure of the previous medical examiner Dr. Jeffery Gofton.

Gofton quit in 2016 after less than 18 months on the job.

Gofton had replaced Dr. Anny Sauvageau, who sued Alberta Justice for wrongful dismissal, alleging her contract was not renewed after she stood up to political interference at work.

In 2011, all of Calgary's medical examiners resigned. Two cited taxing workloads; the other stepped down after an investigation into errors in his autopsy reports.

The medical examiners perform an average of 4,000 post-mortem examinations each year, and investigate nearly 20,000 deaths, according to the office's website.