A day before NBC plans to broadcast the lighting of the Rockefeller Center Christmas tree in front of the network's New York City headquarters, a local union is threatening to pull the lights on the nationally televised event, a media industry blog reported.

Members of the local chapter of the National Association of Broadcast Employees and Technicians have been working without a contract since March, and if NBC executives don't set dates for further negotiations, the union says it will strike during Wednesday's "Christmas in Rockefeller Center," Mediabistro's FishbowlNY reported.

The annual event is a big ratings grabber for the network, owned by General Electric. A strike potentially could disrupt the celebration and the TV special, though it wasn't immediately clear how Rockefeller Center or NBC would handle such a scenario.

The union is accusing NBC of growing "increasingly hostile, ignoring the concerns of the union's membership," and it has created a Web site, NBCStoleChristmas.com, to promote its cause.

"We can't let the Grinch at NBC steal another Christmas from thousands of honest working people," NABET-CWA Local 11 President Ed McEwan said in a news release. "This charade must stop. Christmas is supposed to be a time of goodwill, but the network's management is trying to hide behind their fancy lights while leaving their employees in the dark."

The union says it represents nearly 3,000 of NBC's producers, writers and technicians.

NBC Universal fired back at the union in a statement saying the union canceled three days scheduled for negotiations, Nov. 18, 19 and 20, and has not offered alternative dates.

"Progress can only be made in labor negotiations when the parties are negotiating," the statement read. "It is unfortunate that the union is resorting to threats as opposed to meeting its obligation to engage in collective bargaining."

FoxNews.com's Michelle Maskaly contributed to this report.

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