Several thousand unionized port workers in Canada's western province of British Columbia went on strike after failing to reach a deal to renew an industrywide contract that expired in March, a waterfront employers group said on Saturday.

The British Columbia Maritime Employers Association (BCMEA) said it and the International Longshore and Warehouse Union Canada (ILWU Canada) had met Thursday and Friday in talks supported by the Federal Mediation and Conciliation Service.

"Unfortunately, a tentative agreement could not be reached," the BCMEA said.

ILWU Canada members were on strike at sites across British Columbia, the BCMEA said. Asked for comment, the union said it would issue a statement once there is a resolution to the dispute over the collective bargaining agreement, which covers about 7,500 employees at 30 terminals in the province.

The walkout could have serious consequences for Canada's economy and small businesses, the Canadian Federation of Independent Business (CFIB) said. The group urged the government to ensure port operations are maintained.

On Wednesday, the longshore workers union issued a 72-hour strike notice.

In a Twitter post on Saturday, Canada's Minister of Labour, Seamus O'Regan Jr., said the BCMEA and ILWU Canada remain at the bargaining table working toward a deal, adding that the federal mediators continue to support the parties in their negotiations.