Premier François Legault is now urging Quebecers to wear a mask when they are outside their homes.

"A great way to greatly reduce the contagion is to wear a mask. We strongly recommend that you do so," he said Tuesday, at a provincial briefing on the COVID-19 pandemic.

Before Tuesday, the government had advised people to wear masks in situations where respecting the two-metre physical-distancing rule would be impossible.

Legault, as well as Health Minister Danielle McCann and Public Health Director Horacio Arruda, drove home their message by arriving at their briefing wearing masks themselves, for the first time since the COVID-19 pandemic was declared two months ago.

After undoing his mask, Legault said he was wearing it to make a point: he hopes to see "as many Quebecers as possible" wearing a face-covering outside their homes, to prevent further spread of the virus.

He said it was especially important to follow physical-distancing guidelines and wear a mask as the province opens up.

Legault said there are two reasons the province isn't making the recommendation mandatory — the cost and shortage of masks would make it difficult for everyone to get one, and masks aren't 100 per cent effective at preventing viral spread.

Montreal's transit authority (STM) announced last week it had ordered more than 500,000 reusable masks to be handed out to commuters.

Philippe Schnobb, STM chair, said while it won't be mandatory for passengers, the wearing of masks is recommended.

"If we make it mandatory that will mean we have to put measures to make sure that it would be followed, and I don't think our inspectors have time to give fines for someone who doesn't wear a mask," he said Friday.

The STM has partnered with Exo, the transit authority serving the greater Montreal region, as well as the Laval and Longueuil transit agencies to distribute masks.