By Amanda Becker

(Reuters) - Three anti-union Volkswagen (VOW3.DE) workers have sued the German automaker and the United Auto Workers in U.S. court, alleging that they improperly colluded in the run-up to a union election in Tennessee that the UAW lost.

The lawsuit marks the latest fallout from a hard-fought contest at VW's plant in Chattanooga, where workers voted 712-626 last month not to join the UAW. The union is asking federal regulators to scrap that result and hold a new election.

In their lawsuit, the three workers are seeking a legal injunction that would prohibit VW from making similar agreements with the UAW if another election is held in Chattanooga.

Filed on Wednesday in U.S. District Court for the Eastern District of Tennessee in Chattanooga, the complaint alleges VW provided "thing(s) of value" to the UAW in the unionization drive, violating the Labor Management Relations Act (LMRA).

VW managers helped the UAW in days leading up to the mid-February election by agreeing not to oppose its unionization drive, granting the union access to its property and allowing it to meet with employees during work hours, the lawsuit said.

The LMRA bars employers from paying or delivering a "thing of value" to the labor union representing its employees.

"UAW union officials and Volkswagen management have colluded to deprive these workers of a fair vote from the start," Mark Mix, president of the National Right to Work Legal Defense Foundation, said in a statement.

"Enough is enough, which is why these workers are seeking to prevent further VW assistance to the UAW's organizing efforts," added Mix, whose Washington, D.C. area-based group launches legal actions against unions across the United States.

The group, which does not disclose the identities of its financial backers, is providing free legal counsel to the workers who filed Wednesday's lawsuit.

The lawsuit notes that the UAW has already challenged the election it lost at VW Chattanooga. The agreement in place at the time of the first election is still in effect and the parties would likely adhere to the same terms during future organizing efforts, according to the filing.

"It is likely that Volkswagen will provide Organizing Assistance to the UAW, or things of value similar to it, before a rerun election," the filing states.

A VW representative in Chattanooga declined to comment. But

UAW President Bob King dismissed the accusations made by the trio of workers who filed the lawsuit as baseless.

"The National Right to Work Legal Foundation has a history of frivolous lawsuits trying to stop workers from joining the UAW," King said in a statement on Thursday.

UAW General Counsel Michael Nicholson said in an interview that the UAW and VW agreed not to fight over the union's campaign only after VW was shown by the union that it had the support of the majority of the proposed bargaining unit.

"It's a basic premise of the National Labor Relations Act that employers are entitled to reach agreements with majority-supported unions," Nicholson said.

Harvard Law School Professor Benjamin Sachs said VW "could have recognized" the UAW as the union representing its workers when the organizing agreement with VW was signed. Though the parties agreed instead to proceed to a formal election overseen by the U.S. National Labor Relations Board (NLRB), "the idea VW couldn't give organizers access to the property is meritless," Sachs said.

Wednesday's lawsuit is the latest twist in the UAW's push to unionize a foreign-owned auto plant in the U.S. South.

In its challenge before the NLRB to the Chattanooga election, the UAW has alleged that politicians and outside groups compromised the process by making anti-union statements in the days before the February 12-14 vote.

(Editing by Kevin Drawbaugh and Tom Brown)