Chrysler Group and the UAW said they had had agreed to continue bargaining past the 14 September expiration of the national labour contract. General Motors was also reported to have agreed to a contract extension overnight so talks could continue.

Bargaining between the 'Detroit Three' and the United Auto Workers Union over a new contract to replace the now-expired four-year pact has been going on for several weeks with no deal yet reached.

"Chrysler will continue its efforts to reach a new agreement. Once we have an agreement, it is subject to ratification - a UAW internal process - and then implemented," the automaker said in a statement.

The Detroit News reported that the union had told local branch presidents by text message the Chrysler extension was for a week. The Motown paper added that talks had broken down and that Chrysler CEO Sergio Marchionne had rebuked UAW president Bob King by letter for not meeting with him on Wednesday after he flew in specially from the Frankfurt show. The UAW declined to comment.

"Until now, there have been encouraging signs of a new paradigm governing the relationship between us," Marchionne was said to have written. "You and I failed … today. We did not accomplish what leaders who have been tasked with the turning of a new page for this industry should have done. We did not manage to agree to a set of simple conditions that would have given certainty and peace of mind to the lives of more than 110,000 actives and retirees."

Marchionne reportedly said he was leaving the United States but offered to extend the current contract for another week.

King had said earlier he expected a deal to be reached by the original deadline and to avoid the drama that has accompanied previous contract bargaining.

The UAW sometimes calls a strike after the dealine passes to spur a speedy resolution but is barred from calling workers out at Chrysler and GM under the terms of their Chapter 11 restructuring.

In 2007, the UAW called a 6-1/2 hour strike one day at 11am - an extension to an existing agreement had by then expired - and agreed a new contract by 5.30pm.

The UAW could have called a strike at Ford at midnight Wednesday (14 September) when its current pact expired but earlier agreed an extension so talks could continue.