The Maritime Employers Association reportedly accuse the longshoremen's negotiations tactics — such as not working overtime — of disrupting operations.
Contract negotiations have been ongoing since Dec. 31, 2008, with wages, overtime and job security the sticking points in the mediated talks.
The federal labour minister is "disappointed" with the lockout, which has shut down the major Canadian port. Only the Port of Vancouver is larger.
"I am disappointed that the Maritime Employers Association, Montréal, Quebec and the Syndicat des débardeurs (Canadian Union of Public Employees, Local 375) have been unable to reach an agreement in their labour dispute, which has resulted in a work stoppage," Labour Minister Lisa Raitt said in a statement Monday, noting federal mediators are in contact with both sides and are available to help "at all times.
"I urge the parties to resume bargaining and reach a negotiated agreement as soon as possible."
All commercial activity at the port has been halted — except the grain silos, which are run by the port authority itself — and boats are reportedly being redirected to the United States.
The Port of Montreal, one of the largest in North America, handles more than 20 million tonnes of cargo annually and services more than 40,000 cruise ship travellers a year.
Raitt said the government will continue to "monitor" the situation closely.
Since it's a federal port authority, the government has the authority to force workers back to work.