The Manitoba Government and General Employees' Union has told the province's Progressive Conservative government that its members can, and should, refuse to work on Lifeflight air ambulance calls if there is no critical-care physician on board.

The government was able to find crews to staff flights this week, but is still working on schedules for later in the month.

The staffing issues at the Lifeflight service began after the Manitoba government issued a request for proposals last July to privatize its air ambulance and general transport services.

In a letter last Friday to Health Minister Cameron Friesen, the MGEU said it has a legal opinion supporting its advice to nurses who work on the flights.

'To provide safe emergency medical care, the Lifeflight air ambulance service requires a medical team that includes both a critical-care doctor and a critical-care nurse,' says MGEU's Michelle Gawronsky. (CBC)

"We are advising nurses that they have the right and the professional responsibility to refuse an unreasonable directive from their employer, based on serious ethical, moral, professional and most importantly patient safety concerns," wrote MGEU president Michelle Gawronsky.

The union released a statement this week saying there were "five upcoming instances this month in which the government has not been able to ensure conditions for doctors to feel they can responsibly staff Lifeflight."

A statement from the health minister on Tuesday acknowledged there were difficulties getting staff to keep the air ambulances in the air.

"Our government is committed to ensuring air medical services continue to be available. This week's schedule has been filled and work is continuing to ensure all shifts are appropriately staffed for the remainder of the month," wrote Friesen.

'We encourage Lifeflight doctors to continue to work with government to provide a robust and sustainable air medical service for Manitobans,' Health Minister Cameron Friesen said in a statement. (Jeff Stapleton/CBC)

The PC government's search for a private-sector alternative to the current ambulance system has caused months of tension between it, and the physicians and nurses who work on the aircraft.

The doctors have threatened to quit over concerns about patient care if the service is shifted to a for-profit model.

The MGEU says there are several procedures that Lifeflight nurses are unable to perform, as the work is outside their scope of practice.

"To provide safe emergency medical care, the Lifeflight air ambulance service requires a medical team that includes both a critical-care doctor and a critical-care nurse," wrote Gawronsky.

"Each possess their own specific scope of practice under their medical licences."

The director of Lifeflight declined comment to CBC News.

Friesen's statement to media on Tuesday reiterated the government's promise not to compromise service, but didn't back away from its intention to find a private-sector alternative to the current provincially operated medical flight system.

"We encourage Lifeflight doctors to continue to work with government to provide a robust and sustainable air medical service for Manitobans," he wrote.

"As we have said all along, we will not proceed with any alternate plan that compromises current service and safety levels."