TORONTO -- Canada's largest private sector union is calling for a boycott of General Motors vehicles made in Mexico as part of a campaign to save GM's assembly operation in Oshawa, Ont.

The call from Unifor comes after national president Jerry Dias said he wouldn't call for an outright boycott of GM products because he wouldn't want to hinder workers at GM's other plants in Canada.

Dias said the call for a boycott is not against Mexican workers, but against GM's decision to close the Oshawa plant as it shifts production to a country where worker pay is a 'disgrace.'

"What we're disgusted by is how GM is using these workers as pawns for corporate profit," said Dias.

"We're asking Canadians to stand up to corporate greed. We're asking you to stand up to greedy motors."

The union says consumers can identify vehicles made in Mexico because the vehicle identification numbers start with a three.

Some GM vehicles, including the Chevrolet Blazer, Trax and GMC Terrain are only made in Mexico, while others such as the Chevy Equinox, Silverado and Cruize are made throughout North America.

GM warned that the call for a boycott could create collateral damage across the Ontario economy as parts suppliers in the province that supply Mexico could be hit.

"The threat of collateral damage for Ontario based auto suppliers, auto dealers and workers is concerning," said GM Canada vice president David Paterson in a statement.

Unifor and GM Canada are locked in a battle over the future of the company's Oshawa assembly operations, which the company plans to close by the end of 2019.

The closure will mean the loss of about 2,600 unionized workers and is expected to have a knock-on effect on suppliers in the region.