DETROIT – The UAW is considering staying on strike against General Motors until rank-and-file members approve a tentative agreement, a process that could add more than a week to the length of the work stoppage, the Detroit Free Press has learned.

Negotiations continued Sunday as the strike reached its seventh day.

Three people familiar with the union's thinking said the UAW GM council voted on Sept. 15, when it called the strike, that workers would remain out until the council of local leaders voted to end the nationwide work stoppage. But two UAW local leaders who are on that council told the Free Press it is likely that even after that council vote, workers could remain on strike until membership ratification. A third person affirmed that.

Usually, strikers return to work once a tentative agreement is reached, and they vote on ratification in the next couple weeks.

A source close to GM bargainers expressed concern at the possibility, saying a prolonged strike is bad for the company and the workers. Analysts say the production stoppage alone is costing GM $50 million to $100 million a day.

Likewise, strikers will earn just $250 in strike wages each week and will have to have medical expenses reimbursed through COBRA. In addition, thousands of workers with GM suppliers have been temporarily laid off because of the strike, and GM's Oshawa, Ontario, plant has been idled, with some 4,000 workers temporarily laid off due to a parts shortage from the strike.

Remaining on strike until a tentative agreement is approved is not unprecedented, said two labor experts, who recalled workers staying on strike in 1970 until the entire rank-and-file approved the new contract. As of Sunday morning, one of the main sticking points in talks was GM's refusal to allow temporary workers to receive profit-sharing payouts and to create a pathway for them to become permanent workers.