THE United Auto Workers' (UAW's) return to bargaining with General Motors (GM) within hours of calling the first national strike against the carmaker in 37 years may signal the union's desire for a quick end to the walkout.

Monday's 11am strike followed almost 25 hours of continuous bargaining in Detroit. Talks were scheduled to resume yesterday morning.

The showdown between GM and the UAW, while pivotal to the carmaker's future profit and the union's dwindling membership, is not expected to match the battles the two sides waged during the union's infancy in the 1930s.

Neither side can afford a long strike that cuts GM profit or gives Toyota Motor a chance to win more American buyers and force the closing of even more UAW plants.

The strike idled GM workers at more than 80 GM car assembly and parts operations in the United States and may cause shutdowns throughout Canada and Mexico. A prolonged walkout threatens supplies of such vehicles as the Buick Enclave, the carmaker's hopes for ending seven straight years of US sales declines.

"Toyota is probably just waiting to pounce, to take more market share," said Mr Jules Crystal, a labour lawyer, referring to Toyota's claim to 16.2 per cent of the US market so far this year from 9.3 per cent in 2000. GM's share in that span fell to 23.6 per cent from 28.1 per cent.

The dispute highlighted the conflicting goals of GM's Mr Rick Wagoner, 54, in his eighth year as chief executive, and the UAW's Mr Ron Gettelfinger, 63, in his second term as union president.

Mr Wagoner is using the negotiations to cut labour and health- care costs that contributed to US$12.4 billion (S$18.6 billion) in losses in 2005 and last year.

Mr Gettelfinger seeks to preserve pay, benefits and jobs, while US carmakers GM, Ford Motor and Chrysler shed sales and market share to Toyota and other Japanese rivals.