GM spokesman Dan Dolan said negotiators met at the Delphi East operation from midmorning to early in the evening. At the Flint Metal Centre, talks started at in the morning and were still going early in the evening, company spokeswoman Mary Irby said.

A total of 9,200 United Auto Workers are on strike at the two plants. Members of UAW Local 659 struck first, walking off the job at the Flint Metal Centre on June 5. Workers from UAW Local 651 started their walkout June 11 at Delphi East, which makes spark plugs, filters and various instrument components.

The strikes have forced the temporary lay off of 1,86,000 GM workers in North America. The company's strike losses were $1.2 billion in the second quarter and have continued to rise at about $80 million a day, analysts estimate. Flint Metal workers walked off the job overhealth and safety grievances. Company and Union officials are also in a dispute over $300 million in new investments GM promised in exchange for work rule changes that would increase productivity.

At Delphi East, in addition to health and safety disputes, there is contention over what Union leaders say are GM's plans to shift work to outside suppliers and eliminate 2,500 of the current 5,800 jobs.

On Sunday Union leaders from GM locals around the country are expected to start gathering in Flint for an information meeting called for Monday by UAW Vice President Richard Shoemaker.Also on Sunday, 7,000 workers at the Saturn plant in Spring Hill, Tennessee, are scheduled to vote on a strike authorisation request. The Saturn plant is the last of GM's US car factories still in production.

The union has threatened other strikes at GM component operations in Dayton, Ohio, and Indianapolis, Indiana, as well as the Corvette plant in Bowling Green, Kentucky. Lawyers for GM and the UAW are scheduled to startarbitration hearings Wednesday in Detroit over GM's claims the strikes are illegal.

GM filed a grievance against the union in June. The company says the strikes violate its contract with the union because they are really over product allocations and capital investments -- disputes that can only be settled through arbitration and not strikes.

The contract does permit strikes over health, safety and production standards issues such as line speeds.