United Auto Workers members are planning to strike at Fiat Chrysler Automobiles US plants as soon as this evening (7 October) in what Reuters said would be  the first work stoppage since 2007.

A strike at its US operations could cost the automaker US$40m a week in operating profit, Sean McAlinden, chief economist with the Center for Automotive Research, told the news agency.

Workers at several plants in Kokomo, Indiana, and at least one in Michigan received notices to be ready to strike but it was not clear whether all Fiat Chrysler plants would be involved, Reuters said.

"FCA US confirms that it has received strike notification from the UAW. The company continues to work with the UAW in a constructive manner to reach a new agreement," the automaker said in an emailed statement.

Kristin Dziczek, labor analyst at the Center for Automotive Research, told Reuters the last time the UAW took the company, then known as Chrysler, out on strike it was a “Hollywood strike,” as in “just for show” in 2007. That strike, in the second week of October, lasted six hours.

The strike weapon was not available to the UAW until this year for Fiat Chrysler or General Motors Co (GM.N) as part of the 2009 government-sponsored bankruptcies at those companies, the report noted.

Arthur Schwartz, a laboyr consultant and former negotiator with GM, said, "This is the union's play now. It is up to them what happens." He added UAW president Dennis Williams would not want a lengthy strike because of the pain it could inflict on his members and the harm to Fiat Chrysler.

"Chrysler is not in great financial shape, no matter what the UAW members may think. The company is the weakest of the (Detroit Three) so a long strike would hurt them," he told Reuters.

Harley Shaiken, labour professor at the University of California, Berkeley, said: "A strike deadline is not a strike. Strikes are very rare now in the entire economy."

On Tuesday, Reuters said, the UAW had warned FCA workers at its US operations were preparing to strike unless a new contract agreement was reached, the company said. The UAW notified Fiat Chrysler that the current four-year contract extension would expire at 11:59 pm on Wednesday. The notice did not specify whether the union would call a strike at some or all US Fiat Chrysler assembly, transmission and stamping plants and other operations where 40,000 UAW members work.

This year, negotiators for both sides reached a tentative agreement but that was later spurned by the union’s rank and file members.

Schwartz told Reuters a prolonged strike would hurt the union's efforts to convince workers to join the UAW in the US south at foreign-owned automakers such as VW, Daimler and Nissan Motor.