She said the petition, submitted last week, will be rejected because the casino's parent company, Trump Entertainment Resorts, is appealing a previous NLRB ruling that it must bargain with the union.
"This is the right decision because we know we are the majority, and the majority of dealers support our union at Trump Plaza," said Mary Beth Litchholt, a 22-year veteran dealer there. "It would be wrong for the employer to gain an advantage by violating the law. We won our election, and they have an obligation to bargain, plain and simple."
The decision was first reported by The Press of Atlantic City.
The union was approved by 68 percent of those who voted in March 2007, with 32 percent opposed. The United Auto Workers says the decertification petition was filed by about the same percent of dealers who didn't support the union in the first place.
Trump Entertainment has never recognized the outcome of the vote, claiming it was tainted by a pro-union rally just before balloting.
The UAW represents dealers at four Atlantic City casinos - Trump Plaza, the Tropicana Casino and Resort, Bally's Atlantic City and Caesars Atlantic City - but has yet to reach a contract with any of them after 2 1/2 years.
It has authorized strikes at each casino except Trump Plaza. No dates for a potential walkout have been set.
If the NLRB had approved the decertification petition, it could have ordered another election, this time over whether to dissolve the union as a bargaining agent for Trump Plaza dealers. Several labor experts predicted that in the current recession, with casino revenue plunging and jobs disappearing in Atlantic City, it would have been harder for the union to win such a vote.