(Adds JCI response, update on Unifor's efforts at Toyota Ontario plants)
DETROIT, June 4 (Reuters) - Unifor, which represents Canadian auto workers, will strike at Johnson Controls Inc's Whitby, Ontario, plant if the parts maker does not reverse its plan to close the facility in a couple of years, the head of the union said on Wednesday.
Unifor President Jerry Dias said at the United Auto Workers convention in Detroit that the Canadian union would "shut down GM" at its Oshawa plant, which gets interiors and seats from Whitby, unless JCI changes its plans.
Dias said the deadline for JCI to act is August, when the current contract for 300 workers at Whitby expires. Unifor-JCI contract talks at Whitby will probably begin late this month, he said.
JCI officials said the company did not comment on labor negotiations.
GM said the issue was between JCI and Unifor. "We are not able to comment on labor issues facing an independent business," GM said.
Dias said he had met with JCI officials near Detroit on Tuesday to warn them that the union would strike. He said there was no immediate reaction from the company.
JCI has not made any physical moves to shut the Whitby plant, Dias said.
"They have given us official notification, but I'm telling you, our plant does not close," Dias told reporters on the sidelines of the UAW convention in downtown Detroit. "We will strike the operations unless they reverse their decisions. That is crystal clear."
Dias said JCI's current project to supply interiors to GM at Oshawa runs for about two more years. JCI has said the plant will close after that, he said, and the jobs would move outside Canada.
Unifor, Canada's largest private-sector union, has individual contracts with the JCI plants in Whitby and at Tillsonburg, Ontario.
At its sprawling Oshawa facilities, GM assembles the Chevrolet Camaro and Impala, as well as the Cadillac XTS and Buick Regal. JCI produces door pads and floor consoles for the Impala, as well as seats for the Camaro.
Shares of JCI were up 1.1 percent at $49.08 in afternoon New York Stock Exchange trading, while GM rose 4.3 percent to $36.78.
TOYOTA ONTARIO PLANTS
Dias said Unifor was progressing slowly in its effort to organize workers at Toyota Motor Corp's Ontario plants.
He said the union had collected more than 3,000 signatures of Toyota workers at two plants in Cambridge and one in Woodstock.
In April, Unifor delayed plans for workers at the Toyota plants to vote on whether to unionize. The company had said 7,500 employees were eligible to be in the bargaining unit and to vote, about 1,000 more than Unifor had expected.
Dias on Wednesday said the union was checking a list of the names of the 7,500 to make sure that all of them are indeed eligible to be in the bargaining unit.
A majority of workers must vote "yes" for a union to be formed. (Additional reporting by Ben Klayman in Detroit and Solarina Ho in Toronto; Editing by Lisa Von Ahn)