General Motors told over 1,200 workers in the US and Canada they were being temporarily laid off due to the United Auto Workers' ongoing strike.

The fresh round of cuts - which took place from Monday (23 September) was on top of an estimated 4,500 temporary layoffs GM and its suppliers handed out to employees as of Friday, Jerry Dias, president of Canadian trade union Unifor, which represents GM and other auto workers in Canada, told cnbc.com.

Citing company and union officials, the business news website said the latest furloughs included about 525 hourly employees at the automaker's jointly operated DMax engine facility in Ohio and about 700 at GM's St Catharines, Ontario, powertrain plant.

All this brings the total number of workers temporarily out of work to 3,725 at GM and at least 2,000 at suppliers.

The total likely is significantly higher as there wasn't a way to track all of GM's suppliers, cnbc.com said.

GM has said it planned to resume operations at plants that have been hit by the strike "as quickly as possible" once a new deal is struck with the UAW.

Cnbc.com noted Julie Fream, president and CEO of auto parts trade group the Original Equipment Supplier Association, said last week the "vast majority of North American supplier plants shipping product to GM will need to adjust their production schedules" if the strike continued for a week or more. The group declined to tell cnbc.com how many suppliers had been impacted by the UAW strike so far.

Magna International, the Ontario Tier 1 that supplies several components to GM, confirmed to cnbc.com approximately half of its divisions in the US and Canada have "started to experience sporadic layoffs".

Magna spokeswoman Tracy Fuerst also declined to say how many of her company's workers had been laid off temporarily. The company employs about 170,000 people globally. Fuerst said some divisions have been able to "offer training and/or conduct maintenance and inventory to help mitigate the downtime in the short term".

Magna, Fuerst told cnbc.com, continued "to monitor the situation and we remain hopeful for a quick resolution". GM was Magna's largest customer in 2018, representing 15% of its sales.

The report noted Citigroup, in a note to investors last week, mentioned Magna as well as American Axle, Lear and Aptiv as being suppliers that would be most affected by the strike. Representatives for the other companies did not respond to cnbc.com requests for comment.

The UAW strike is estimated to cost GM up to US$100m a day in lost production, cnbc.com said, citing Wall Street analysts.

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