Chrysler had reportedly sought $700 million in government support toward a $3.6 billion investment for the plant, but the deal was scuttled when federal and provincial officials pressed Chrysler on how much of its investment would be spent in Ontario, it was reported in March.

Marchionne, who is also the CEO of Fiat, which owns Chrysler, said on Wednesday that his company is already investing in the Windsor plant without government funds.

Chrysler has said it will develop and produce its next-generation minivan in Windsor, Ontario, but has not detailed the scope or duration of that production work, nor how much it will spend to re-tool the plant. It is unknown if the company scaled back its investment after the government talks failed.

A vocal opponent to any government incentives, Ontario conservative leader Tim Hudak, was defeated in provincial elections two months ago. The province's Liberal economic development minister said on Wednesday that the government was "always prepared" to talk with Chrysler.

Marchionne said on Wednesday the automaker could not hold up its plans.

"If in fact the federal government or the province of Ontario think that there is a proposal that would be of interest to Chrysler, I think we're more than willing to sit down and discuss it," Marchionne said on an earnings conference call.

"But, today, I think the horse left the barn, and the (Chrysler) investment is going into Windsor and that's all there is to say."

Jerry Dias, president of the Unifor union, which represents workers at the Windsor plant, said there is "no question" that federal and provincial governments are interested in coming to an agreement with Chrysler.

"I would expect that the provincial government is going to reach out, but it's crystal clear that the provincial government and the federal government have left the door wide open for Chrysler," Dias said.

(Reporting by Susan Taylor in Toronto and Bernie Woodall in Detroit; editing by Gunna Dickson)

By Bernie Woodall and Susan Taylor