United Auto Workers members on strike picket outside General Motors' Detroit-Hamtramck Assembly plant on Sept. 18, 2019 in Detroit. Michael Wayland / CNBC

DETROIT — Thousands of Canadian auto industry workers have been furloughed, with more temporary layoffs coming, as negotiations on a new labor contract between General Motors and the United Auto Workers drags into a fifth day. Jerry Dias, president of Canadian trade union Unifor, which represents GM and other auto workers in Canada, said in an interview Friday that roughly 4,500 of his members have been temporarily laid off because of the strike so far. He said that includes about 2,500 workers at GM's Oshawa Assembly plant in Ontario, Canada, and 2,000 people who work for GM's suppliers.

The suppliers are "getting clobbered," Dias said, adding non-unionized plants are being affected as well. Roughly 48,000 UAW members with GM have been on strike since Monday after the two sides failed to reach a deal by a Saturday night deadline. It is the union's first national strike against the automaker since a two-day work stoppage in 2007. The strike at GM's U.S. plants has disrupted operations at the automaker's other facilities as well as at some of its suppliers. While GM wouldn't confirm Dias' numbers, the company said Friday that it has fully idled production at the Oshawa plant and temporarily laid off 2,000 workers there. The automaker initially said it furloughed roughly 1,200 workers at the plant earlier this week, but it has since revised that number higher and expanded the temporary layoffs at the Oshawa plant. "We plan to resume these operations as quickly as possible upon resolution of the UAW strike," GM said in an emailed statement. According to Dias, GM plans to temporarily lay off 700 additional workers at the company's St. Catharines, Ontario, plant on Monday and will "re-evaluate" production at its CAMI plant in Ontario next week, depending on the length of the strike. GM spokesman Dan Flores declined to comment on the automaker's plans next week, saying the company is "monitoring the situation on an ongoing basis." GM makes engines at St. Catharines and the Chevy Equinox at the CAMI plant. The Oshawa Assembly plant makes the Chevrolet Impala and Cadillac XTS, both of which are scheduled to be discontinued, as well as some pickups that are also being phased out. It's unknown how many workers at suppliers in the U.S. have been affected by the strike. Flores said the company knows the strike is "impacting a variety of our stakeholders, including our suppliers," but he declined to speculate on how many workers have been affected. GM said other operations in Canada, including the CAMI assembly plant, stamping operations in Oshawa and St. Catharines powertrain plant continue to operate.