Layoff notices have been handed out to hundreds of workers at the General Motors transmission-making factory in St. Catharines, Ont., as effects spread from a strike that started Sunday at GM's CAMI plant in Ingersoll, Ont.

At least 255 of the 350 union workers at the St. Catharines plant will be laid off starting Monday, said Unifor 199 chairman Tim McKinnon.

"We supply about 90 per cent of (CAMI's) transmissions, so it's related to that," he said.

"Even though they were down, we ran all week ... We have a lot of transmissions stockpiled now because we didn't know if they were going to resolve it this week or not. It doesn't look like they're going to."

He said even if the strike at the plant that makes Chevrolet Equinox vehicles is resolved over the weekend, the St. Catharines workers will be out for at least a week. He added his union supports the CAMI workers' strike despite the layoffs.

3 plants affected

GM Canada, meanwhile, says in an update posted Thursday on its website that it has made "production adjustments" at St. Catharines and at two American engine plants in Spring Hill, Tenn., and Flint, Mich., as a result of the strike.

A spokeswoman said in an email no further details would be available.

Earlier Wednesday, parts maker Magna International announced it would stop supplying parts to the CAMI plant, a decision it said would affect output at a few of its facilities in Ontario, without being specific.

Unifor Local 88, the union representing the 2,500 striking workers at CAMI, said Thursday it has invited management to get talks rolling again in hopes of reaching a settlement.

But local president Dan Borthwick said its demand that the plant be designated the lead producer of the Equinox to ensure production and jobs aren't shifted to Mexico hasn't changed.

"We're just trying to be responsible and see if there's any way we can bring a quick resolution to the work stoppage and minimize the effects on our members and the suppliers and the surrounding community," he said.

"With that said, the company has to understand our goals, the lead producer letter, our economics and our contract language are still outstanding issues that need to be resolved."

When asked if GM would meet with the union, the spokeswoman sent a copy of GM's statement posted last Sunday which expressed disappointment that talks had broken down and encouraged Unifor to resume negotiations. She wouldn't say if any meetings have been scheduled with the union.

Job security has become more of an issue for the union since GM shifted production of its Terrain SUV from the plant to Mexico earlier this year at a loss of more than 400 jobs.