GM Canada plans to announce an investment in Canadian research and development at its complex in Oshawa, Ont., on Tuesday.

Kevin Williams, president of GM Canada will deliver the news at the company's Canadian Engineering Centre.

Prime Minister Stephen Harper, federal Finance Minister Jim Flaherty and Ontario Premier Dalton McGuinty are among the politicians who will attend the event.

The Oshawa plant builds many GM models — from the Impala and Camaro to the Chevrolet Equinox and Buick Regal — and employs more than 4,500 people.

GM Canada declined to provide more details about the event.

Last August, the company announced a $117-million investment at the assembly plant to prepare it  to build the new Cadillac XTS.

The Oshawa assembly plant has had major changes in the last two year, with new vehicle models and expanded production that has added two new shifts and 1,300 jobs.

The federal and Ontario governments invested a total of $10.5 billion in GM Canada in 2009 as the automaker struggled to survive the economic downturn.

In Canada, the company shut down a truck plant in Oshawa and a transmission plant in Windsor, Ont., and cut its workforce.

In June, GM announced plans to close the older part of its Oshawa car plant by June 2013, potentially laying off 2,000 workers.  The consolidated plant produces the Chevrolet Impala and the Equinox and was originally slated to be closed in 2008 before a series of extensions delayed its demise.

Since the restructuring, GM has eliminated all but four of its brands and has transformed itself into a much leaner, more profitable company.   

GM Canada employs about 10,000 people at its Ontario-based operations. The company operates assembly plants in Oshawa and Ingersoll and parts plants in St. Catharines.