By Paul Vieira and Colin Kellaher

The union representing 1,700 workers at General Motors Co. plants in Canada said Thursday it reached a tentative agreement with the auto maker that includes restarting vehicle assembly at a factory in Oshawa, Ontario.

Unifor, Canada's largest private-sector union, said GM would spend about 1.3 billion Canadian dollars, or the equivalent of about $1 billion, to reopen the assembly plant, east of Toronto, to produce light- and heavy-duty trucks. Unifor president Jerry Dias said hiring could begin in August 2021, with the first trucks coming off the assembly line starting in 2022.

In 2018, GM announced its intention to shut down vehicle assembly in Oshawa, which put about 2,600 people out of work. Last year, GM agreed to convert the plant into a part-making operation that would employ 300.

"We never gave up hope, and neither did GM," Mr. Dias said, adding he anticipates GM will hire at least 2,000 workers. "We will become a complete assembly operation once again."

The decision to restart Oshawa comes as demand for pickup trucks has continued to strengthen through the coronavirus pandemic as more people look for bigger and more rugged vehicles. Mary Barra, GM's chief executive, confirmed the company's plans for Canada during a conference call tied to the auto maker's third-quarter earnings.

Prior to the GM agreement, Unifor negotiated new labor deals this fall with Ford Motor Co. and Fiat Chrysler Automobiles NV that also included roughly C$5 billion in investment commitments to produce vehicles in Canada. Ford, for instance, agreed to build electric vehicles at its factory in Oakville, Ontario, a suburb of Toronto.

GM's original decision on Oshawa in 2018 dealt a blow to Canada, as officials worked hard to preserve employment in the Canadian auto sector in talks to renegotiate a North American trade pact with governments in Washington and Mexico City.

Write to Paul Vieira at paul.vieira@wsj.com and Colin Kellaher at colin.kellaher@wsj.com

(END) Dow Jones Newswires

11-05-20 1134ET