After downplaying the effectiveness of non-medical face masks, both the chief public health officer and federal health minister now say they would wear them in cases where physical distancing isn't possible in public.

Theresa Tam, the country's top doctor, said Tuesday that while the scientific research "is not quite there" yet on the effectiveness of non-medical masks in stopping the spread of COVID-19, she wouldn't hesitate to use a mask when grocery shopping or riding transit.

"That's one option," she said of wearing a mask. "It is an added layer of prevention and protecting the spreading to others."

Minister of Health Patty Hajdu looks on as Chief Public Health Officer Theresa Tam responds to a question during a news conference in Ottawa. (Adrian Wyld/Canadian Press)

Tam has suggested a t-shirt or bed sheet could be fashioned into a homemade mask. But medical-grade masks should be strictly reserved for health care professionals, given the ongoing shortages, Tam said.

Health Minister Patty Hajdu said she hasn't had to wear a mask to this point because she's been able to maintain that two metre distance between herself and others — but she would wear one if it meant protecting others in confined spaces.

She said she would probably feel the need to "fiddle with that mask, given the newness" — which is one of the public health risks associated with wearing a mask.

There are concerns that wearing a mask might encourage people to touch their faces more than they normally would, which also could lead to infection.

Watch: Dr. Tam, Hajdu say they will wear masks when in public

Canada’s Chief Medical Officer Dr. Theresa Tam and Health Minister Patty Hajdu say they'd wear masks when in public in cases where they're unable to maintain physical distancing to protect others. 1:41

Prime Minister Justin Trudeau said today he will follow the advice of medical professionals on the mask question. He said homemade masks are a sensible solution as they essentially act like a shirt sleeve — a place to catch a cough or sneeze without spreading it around.

"My understanding of what Dr. Tam explained yesterday is that if people want to wear a mask, that's OK. It protects others more than it protects you, because it prevents you from breathing or speaking moistly on them."

(The prime minister cringed visibly after the words "speaking moistly" left his mouth. "Oh, what a terrible image," he said.)

Watch: Trudeau says masks will prevent people from 'speaking moistly'

While he points out that he's not a medical expert, Prime Minister Justin Trudeau said he understands that masks can help protect people from "breathing or speaking moistly" on others. 1:15

While Canada's two top health authorities said they'd wear masks while in public, they cautioned that masks should be worn in conjunction with pursuing other hygiene practices, such as frequent hand-washing.

The commitment to wearing non-medical masks in public comes after the Public Health Agency of Canada changed its recommendations on the medical devices Monday.

While Tam and other public health officials have discouraged healthy people from wearing masks, the public health officer said Monday that homemade masks might actually help to slow the spread of COVID-19 as they can catch wayward droplets from pre-symptomatic and asymptomatic people.

"It's not necessarily there to protect myself. I think there has to be that reality check. I still have to do the hand-washing and still do the physical distancing as much as possible," Tam said. "I think that is reasonable and feasible advice."