MORE than 10,000 workers began industrial action at three of the biggest car makers in the US on Friday, their union says.

Members of the United Autoworkers Union stopped work at three plants owned by the “Big Three” car makers, General Motors, Ford and Stellantis after their labour contract expired at midnight on Thursday.

Addressing members on a live Facebook call, UAW’s president Shawn Fain said: “Tonight, for the first time in our history, we will strike all three of the Big Three at once. We are using a new strategy, the ‘stand up’ strike. 

“We will call on select facilities, locals or units to stand up and go on strike. This strategy will keep the companies guessing. It will give our national negotiators maximum leverage and flexibility in bargaining. And if we need to go all out, we will.” 

Mr Fain added: “This is our generation’s defining moment. The money is there. The cause is righteous. The world is watching. And the UAW is ready to stand up.”

The three initial plants closed by the strike are GM’s Wentzville, Missouri mid-size truck plant, Ford’s Bronco plant in Michigan and the Jeep plant in Toledo, Ohio, owned by Stellantis.

The sites closed make some of the Big Three’s most profitable trucks, including the Ford Bronco sport utility vehicle, the Chevrolet Colorado pickup, the GMC Canyon and Jeep’s Gladiator and Wrangler. 

At the Toledo Jeep plant, assembly line worker Candace Bowles, said it felt “strange” to walk off the job. “I didn't want to have to do it but I’ve got to do it,” she said.

The UAW has demanded a 40 per cent pay increase for its roughly 140,000 members over four years, which, they say, is comparable to the rise in pay for company executives.

The union is also demanding a four-day working week, a return to automatic inflation related pay increases and stricter limits on how long workers can be considered “temporary” staff, who are not entitled to receive union benefits.

Ford said the demands of the UAW would more than double its US employment costs.

Last month, 97 per cent of UAW members voted to authorise a strike, insisting that the companies could afford to be far more generous in the new contract after reporting a record $21 billion profits over the last six months.

“In my opinion we are owed this,” said Paul Raczka, who works in a Stellantis factory in Michigan making Jeep Grand Cherokees.