The United Auto Workers union has 816 members at the Volkswagen plant in Chattanooga, or about 55 percent of the total blue collar workforce, according the union's latest disclosure with the U.S. Department of Labor.
But, a rival labor group said Wednesday that the UAW number is "unsubstantiated and in no way an official count."
Sean Moss, the American Council of Employees' president, said the UAW's claim of 55 percent of hourly workers is "merely part of the UAW's push to avoid an employee election."
The UAW filing comes as the union works toward gaining collective bargaining rights at its first foreign-owned plant in the South. And the union's case for recognition could be bolstered by a leadership shakeup at the German automaker that has left a former union chief, Berthold Huber, as the interim chairman of the world's No. 2 automaker.
The UAW last year lost a union vote 712 to 626 at the Chattanooga plant that featured heavy campaigning by Republicans such as U.S. Sen. Bob Corker. Huber wrote workers at the plant before the vote urging them to support the UAW.
"I recommend that you choose to have a democratic voice in your work place and vote for union representation by the UAW," Huber wrote in December 2013. "Thus you will become a part of a global family of solidarity."
UAW Local 42 in Chattanooga has already qualified for the top tier of a new labor policy created at the VW plant after an independent auditor verified the union had signed up at least 45 percent of blue collar workers at the plant.
ACE, has qualified for the lowest tier of at least 15 percent of workers, which grants less frequent access to plant meeting rooms and discussions with managers.
Moss said the UAW's claim of 55 percent of hourly workers "a clear response to ACE's recent progress in working with management to establish a works council in Chattanooga."
He said ACE's recent discussions with management have confirmed what its officials already knew -- that the UAW is legally incapable of establishing a works council.
"Certainly, our progress threatens employee support for the UAW, and that's why we are now seeing the UAW push to avoid an election and instead be recognized through card check," Moss said.
Mike Cantrell, president of UAW Local 42, said last week that the union has more than 50 percent of the blue-collar workers and would like VW to recognize it by counting the sign-up cards.
"We hope VW accepts the cards," he said, adding that the UAW doesn't want another election. "People are still trying to make a lot of trouble."
VW management has been under heavy pressure from powerful worker representatives because the U.S. plant is alone among the company's major worldwide plants without labor representation. The company wants to create a works council at the Tennessee plant to represent salaried and hourly workers. Under that model, wages are bargained through the union, while the council negotiates matters like job security and working conditions.
Huber took over the helm of Volkswagen last week after the shock resignation patriarch Ferdinand Piech, who had shaped the company's destiny for more than 25 years. Piech had criticized CEO Martin Winterkorn in an interview with Germany's Der Spiegel magazine, saying he was "at a distance" from him. Other board members -- including labor representatives who make up half of the 20-member supervisory board -- backed Winterkorn.