Port of Montreal terminal operators have threatened to shut down most operations as of Sunday after providing a "final, comprehensive offer" to the longshore union.

If the Canadian Union of Public Employees Local 375 does not accept the offer by Sunday at 8:00 p.m. "only essential services and activities unrelated to longshoring will continue at the Port of Montréal from 9 p.m. on Sunday," the Maritime Employers Association said in a statement on Thursday.

So far, two terminals operated by Termont, representing about 40% of Montreal's container traffic and 15% of total port volume, have been shut down by the union's strike, which began on Oct. 31.

If the operators' offer is not accepted, all longshoring at the port would be locked out, the association said, adding that its pay offer represented a "cumulative increase" of over 20% over six years.

A CUPE spokesperson said on Friday "an offer has been made and the union is looking at it."

West Coast ports including Canada's largest port of Vancouver have also been mostly shut down since Monday due to a labor dispute, impacting exports of canola oil and forest products. Bulk grain exports are not impacted.