Autoparts maker Magna International announced Wednesday that it has suspended the supply of parts to CAMI, the Ingersoll auto manufacturing plant that's been crippled by a labour dispute.

The three-day old strike began when unionized workers walked out Sunday night over job security and General Motors' future investment in the factory, which churns out the Chevy Equinox, a vehicle that is also manufactured at two separate plants in Mexico. 

"Due to a strike in effect since Sept. 17 at the CAMI Automotive Inc. facility in Ingersoll, Ontario, Magna International has suspended the supply of parts to the CAMI facility," a release from Magna said Wednesday. 

"This suspension of supply to CAMI affects the output at a few Magna facilities in Ontario," it stated. 

A spokesman for the company would not comment any further when reached by phone. 

Magna International is one of the largest autoparts manufacturers in the world and it's not known how many of its workers may be affected by the walkout at the CAMI plant. 

"It's impossible to tell," Tony Faria, an auto industry analyst with the University of Windsor said. ""Magna would certainly know. Anyone outside Magna is not likely to know the exact numbers."

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Toni Faria is the co-director Office of Automotive and Vehicle Research at the University of Windsor. (CBC)

Faria said the same is true of the number of workers who work in other autoparts plants that supply CAMI. He estimates tens of thousands of people could be affected. 

"I don't know exactly how many workers outside the CAMI plant are dependant on it, but the normal spin off number that's used is there are at least seven people who owe their jobs to one person employed in the plant," he said. 

"If we take that for the CAMI plant there could be well more than 20,000 people," Faria said. "A lot of them will be impacted, some of them immediately." 

Faira noted the Qualtech seating plant in London is likely affected by the labour dispute at CAMI in Ingersoll. 

"They're likely on layoff right away," Faria said. 

Calls to Qualtech were not returned at the time of publication.