The port's employers locked out 1,200 dockworkers after they rejected a "final" contract offer Sunday, closing four major container terminals.

Longshoring activity at the Port of Montreal is set to grind to a halt as an employers’ group locks out 1,200 union members.

Workers are locked out at Canada’s two biggest ports on Monday, after Montreal longshore employees rejected a contract with their employers group on Sunday night. Dock workers at British Columbia’s ports, including Vancouver, have been locked out since last Monday as employers push them to approve to a new collective agreement.

Canada’s labor minister said Tuesday he is intervening to end lockouts at the country’s two biggest ports. Labor Minister Steven Mackinnon said the negotiations have reached an impasse and he is directing the Canada Industrial Relations Board to order the resumption of all operations at the ports and move the talks to binding arbitration.

Canada on Tuesday moved to end labor disputes at the country's two biggest ports, Vancouver and Montreal, citing economic damage and the potential for driving away trading partners. It was the second time in a few months that the Liberal government has stepped in to halt a dispute.

Labour Minister Steven MacKinnon says he’s ordering the Canada Industrial Relations Board to impose binding arbitration to end work stoppages at ports in Vancouver and Montreal after negotiations reached an impasse.

Canadian Labour Minister Steven MacKinnon said on Tuesday he had directed the country's labor relations board to order an end to disputes at the ports of Vancouver and Montreal, citing the economic damage.