OTTAWA -- Canadian employers are firing or putting on unpaid leave thousands of workers who refused to get COVID-19 shots, squeezing an already tight labour market and raising prospects of potentially disruptive legal challenges.

as a central part of his successful campaign for re-election in September, setting a precedent that has spread from the public to the private sector.

The mandate for federal workers is one of the world's strictest, and the government has extended it to federally regulated spaces, which include airports, and to air and rail travellers.

Across Canada, hospitals, banks, insurers, school boards, police and some provincial administrations are now

Unvaccinated workers whose livelihoods are on the line - in a country where more than 83% of the eligible population over 12 years old have had their shots - are flooding labour lawyers with calls.

Air Canada and WestJet airlines alone, where well over 90% of staff are vaccinated, are suspending hundreds who are not, and demanding that new hires get inoculated. Toronto transit agencies are likewise putting hundreds on unpaid leave and reducing some services.

Ottawa Hospital, the capital's largest and where more than 99% of staff are fully vaccinated, put on unpaid leave 186 people who failed to prove they were. Services will not be cut, however, said spokeswoman Michaela Schreiter.

While the unvaccinated have some hopes of collecting severance pay or employment insurance, the legal advice that many are getting is that simply not wanting the shot is not grounds for a lawsuit.

"Most people are really unhappy because they want to ... force the employer to change the policy," said Paul Champ of Champ & Associates in Ottawa, whose firm has fielded 20 to 30 calls a day from unvaccinated workers. "I've been very clear to people that that's not going to be successful."

Only strict religious or medical exemptions are being accepted by most employers, who have a right to impose health and safety conditions in the workplace, Champ said.

JOBS SQUEEZE

However, to avoid losing thousands of nurses and other medical staff and being forced to cut services, the Quebec provincial government on Wednesday dropped its previously announced inoculation requirement for healthcare workers, and Ontario said it would not introduce one.

"Implementing a province-wide vaccine mandate for hospital workers can negatively impact the care patients receive," Ontario Premier Doug Ford said in a statement, underscoring the way the mandates can exacerbate a labour shortage.

Some 64% of firms say they are facing , which are preventing more businesses from meeting growing demand, the Bank of Canada said last month.

The jobs market will face added pressure beginning Nov. 15, when as many as 20,000 unvaccinated federal workers - out of some 300,000 - are due to be put on unpaid leave.

"Departments and agencies will assess operational needs ... and are focused on ensuring that there is no noticeable impact on service," said Genevieve Sicard, a spokeswoman at Canada's Treasury Board, which oversees the civil service.

The Treasury Board said it had no knowledge of a legal challenge yet, though that seems only a matter of time.

"There are a lot of people willing to take this to the end because they can see the loss of one person's rights are a loss of everyone's rights," said Stacey Payne, founder of Feds for Freedom, a group of federal employees who say the mandates infringe on their privacy and freedom.

Unions could have some success in challenging vaccine mandates for people who work from home and do not interact with others, said Daniel Lublin, founding partner of Whitten & Lublin in Toronto.

The mandates are "a one-size-fits-all approach," he said.

".. And the problem I have with that is that Canadian employment laws always look at context."

Workers also have a legal argument for severance pay or for employment insurance, lawyers said. Employment Minister Carla Qualtrough has argued that those who lose their jobs because they refuse to get vaccinated should not collect employment insurance.

"A lot of people were playing this out to the wire to see if companies were actually going to fire them," said Lublin. "If they do get fired, I do think that they're going to fight it."

(Additional reporting by Julie Gordon; editing by John Stonestreet and Jonathan Oatis)