The move is likely to threaten GM's North American car production and if the strike action spreads it could have a damaging effect on the US economy.

About 3,400 members of the United Auto Workers union stopped working at the Flint Metal Center, a metal stamping plant, on Friday raising the prospect that more assembly plants could be shutdown.

Talks breakdown

Talks with the union broke down after lengthy talks. The union threatened a strike at a second parts plant on June 11. If this goes ahead it could bring GM's US car production to a halt.

GM accused the striking union of failing to live up to agreements made three years ago to implement new work practices that would make the plant more efficient.

"We do expect a fair day's work for a fair day's pay," GM spokeswoman Mary Irby said. "It's imperative that the local union cooperate with us to get rid of work practices that keep us from running our machines at their full capacity and realising their full potential."

Costly strike

The UAW blamed the strike on GM, accusing the car maker of failing to deliver on its promise for $300 million in new equipment that would ensure the plant's future.

Analysts believe the action could cost GM as much as $200m a week.