Workers at Canadian plants operated by the Detroit Three auto makers have given their union an overwhelming mandate to call a strike against the companies if an agreement on a new contract is not reached by Sept. 19.

Members of Unifor who work at Fiat Chrysler Automobiles NV, Ford Motor Co. and General Motors Co. approved strike action if necessary during votes held on Sunday.

The results in favour of a strike were 99 per cent among workers at Fiat Chrysler, 98.9 per cent at Ford and 97.1 per cent at GM, Unifor said Sunday.

“With this clear mandate our members have demonstrated they are in full support of their bargaining committees, and our direction in this set of negotiations,” Unifor president Jerry Dias said in a statement.

“The bargaining committee will not accept a deal without a commitment to investment in Canada’s auto sector,” Mr. Dias said. “The push for new investments in Canada got a lot stronger today.”

Strike votes are steps in the process of negotiation between the companies and the union. Negotiations began earlier this month and the company and union representatives have been negotiating on local issues before beginning formal discussions on a new national contract.

Unifor will choose one of the three companies as a so-called target company after Labour Day and attempt to negotiate a new contract with that company that will then serve as a template for an agreement with the other two auto makers.

There has not been a strike against any of the Detroit Three auto makers since 1996, when the predecessor union to Unifor, the Canadian Auto Workers, went on strike against GM for three weeks.

Unifor represents about 23,000 workers at the three companies.