Supply shortages stemming from a one-week strike against General Motors Corp.'s Canadian operations are leading to increased plant shutdowns and layoffs in this country.

The walkout by the 36,800 Canadian members of the United Auto Workers union also is putting a dent in the scheduled production of GM's traditional, rear-wheel-drive big cars and its smaller, front-wheel-drive luxury models.

Production of GM's compact trucks, the Chevy S-10 and GMC S-15, also have been affected by the strike.

Analysts yesterday estimated that the closure of GM's 13 Canadian plants alone could cost the company $35 million a week in lost sales.

The strike's growing effect on GM's plants in the United States could boost that weekly sales loss to $150 million, said David Healy, an auto industry analyst with New York-based Drexel Burnham Lambert Inc. "And that will get worse the longer it continues," Healy said of the dollar drain.

GM yesterday closed or drastically reduced production at another three plants and laid off an additional 1,055 hourly workers in the United States. That means the company has shut down a total of 13 plants and laid off 18,525 workers in this country since the Canadian walkout began seven days ago.

The U.S. plant closings and layoffs affect GM's operations in Indiana, Michigan, New York and Ohio. Those plants turn out GM's new, front-wheel-drive luxury cars, the Cadillac Deville and Fleetwood and the Oldsmobile 98.

U.S. assembly lines producing rear-wheel-drive Cadillac Fleetwood and Brougham models, rear-wheel-drive Oldsmobile 88s, and GM's remaining front-wheel-drive X cars, the Chevrolet Citation and Buick Skylark, also have been stopped or slowed by the strike in Canada.

GM has 151 facilities operating in 26 states and 90 cities in the United States, where it employs 350,000 UAW-represented workers. The company has 13 plants in Canada, represented by nine UAW bargaining units.

GM's U.S. and Canadian operations -- as well as the Canadian divisions of other U.S. car companies -- have been closely integrated since 1965 as the result of a trade agreement that grants U.S. manufacturers duty-free shipment of cars and trucks into Canada.

In return for that privilege, the U.S. car companies agreed to produce in Canada the dollar value of vehicles sold there.

GM's Canadian operation last year had $11.2 billion in automotive sales compared with $63.6 billion in sales for its U.S. automotive business.

The union's U.S. leaders, including those whose plants have been hurt by the Canadian strike, say their members aren't upset by the strike. "I haven't heard any of our members complaining," said Bill Spencer, president of UAW Local 5960, which represents hourly employes at GM's brand-new, ultra-modern assembly plant in Orion Township, Mich.