The union representing locked-out dock workers in Montreal was the latest Wednesday morning to say it plans to challenge Ottawa's intervention in court, not long after the union representing locked-out workers in B.C. announced its intention to fight back.

"We will fight this order in the courts. We will fight the arbitrated forced contract in the courts," said Frank Morena, president of the International Longshore and Warehouse Union Ship & Dock Foremen Local 514, which represents the workers in B.C., in a press release Tuesday.

Labour Minister Steven MacKinnon stepped in on Tuesday to get ports in British Columbia and Montreal moving again after employers locked workers out, directing the Canada Industrial Relations Board to order the resumption of all operations and move both sets of talks to binding arbitration.

Container cargo traffic at terminals on the West Coast had been halted since last week, after a labour dispute involving more than 700 longshore supervisors led to a lockout by the employer.

In Montreal, the Maritime Employers Association locked out 1,200 longshore workers on Sunday night after workers rejected what the employers called a final contract offer.

"Negotiated agreements are the best way forward, but we must not allow other Canadians to suffer when certain parties do not fulfil their responsibility to reach an agreement," MacKinnon said in a statement Tuesday.

He said he didn't take the decision to intervene lightly, but that the stoppages created real economic risk.

"It is my duty and responsibility to act in the interest of businesses, workers, farmers, families and all Canadians."

The mechanism used by the minister -- using Section 107 of the Canada Labour Code -- is the same one the government used in August when Canadian National Railway Co. and Canadian Pacific Kansas City Ltd. locked out more than 9,000 workers, grinding railway operations to a halt across the country.

Labour experts at the time said the move appeared to be a workaround negating the need for back-to-work legislation, and warned it could set a dangerous precedent.

"The reason why it's a concerning workaround is because there's no Parliamentary debate. There's no vote in the House of Commons," said Brock University labour professor Larry Savage in a September interview with The Canadian Press, calling it "highly controversial."

The move prompted a court challenge by the Teamsters Canada union.

Now, the unions representing the Montreal and B.C. dock workers say they plan to challenge the minister's intervention this week in court.

In a press release Tuesday, Morena called the government's decision an insult to the union and to workers' bargaining rights.

In the rail and port disputes, business groups were calling for the government to do something as the holdups disrupted supply chains across the country.

On Tuesday, Greater Vancouver Board of Trade president Bridgitte Anderson said in a statement that an estimated $6.1 billion in trade had been disrupted at the B.C. ports.

"The economic toll of the fourth major disruption to our supply chains has been severe," she said.

Unions and labour groups have largely denounced the government's recent interventions.

"Unions will fight this to the end," said Teamsters Canada national president Francois Laporte in a statement Tuesday.

On Tuesday, McGill University sociology professor Barry Eidlin said the government's decision to intervene erodes the incentive for employers to reach a deal at the bargaining table.

"The aim of the lockout was not to pressure the workers; it was to pressure the government to intervene," he said.

In the summer of 2023, a strike by different B.C. port workers lasted 13 days. The government did not intervene using Section 107 for that dispute. Earlier this year, it announced an inquiry into that strike to prevent further major economic disruptions.

This report by The Canadian Press was first published Nov. 13, 2024.