The county contends that the businesses employ deceptive practices to avoid paying the full amount of room occupancy taxes owed the county. Since Jan. 1, 1992, the county has levied a 6 percent tax on the price of a hotel room.

The lawsuit filed this month in Wake County Superior Court names a dozen travel companies as defendants, including Hotels.com, Expedia, Orbitz, Priceline.com and Travelocity.

"We're not trying to gouge anybody. We're just trying to collect what the public is due," said Michael Ferrell, the county attorney.

Since the lawsuit was filed Nov. 3, two more counties that charge room occupancy taxes -- Cumberland and Dare -- have agreed to join the complaint, said Kieran J. Shanahan of Shanahan Law Group, the Raleigh law firm that is representing the county. In addition, the firm has talked to 10 other North Carolina counties that are considering signing up, said Shanahan.

Ferrell said the county is unsure how much money is at stake, but he estimated the defendants may owe as much as $3 million a year over the past five years, or $15 million. In addition, the county is seeking penalties and is asking the court to triple the damages, which is permitted under the state's law on unfair and deceptive trade practices.

The lawsuit contends the online travel companies systematically exploit their business model to cheat Wake County out of a portion of the tax it is owed on each room rented to consumers.

The scenario painted by the lawsuit: The online companies negotiate discounted room rates from hotels and motels, then charge consumers a higher rate. The companies collect taxes on the marked-up price but only remit the tax amount based on the discounted rate to the hotels and motels, which in turn forward the tax to the county. "Defendants keep the difference between the amount charged to the public and the amount remitted to the hotels, motels or inns," the suit states.

That's "absolutely false," said Art Sackler, executive director of the Interactive Travel Services Association, an industry trade organization. "They are wrong on the facts and wrong on the law."

Taxes are collected only on the room rates set by the hotels, not the gross amount collected by the online travel companies, Sackler said. The latter includes a service fee charged by the online travel companies that "isn't subject to the hotel tax," he said.

But Shanahan said that, under Wake County's ordinance, the tax is based on the amount paid by the consumer. "We feel these companies have created a scenario to avoid paying this tax," he said.

Sackler said that about 20 such lawsuits have been filed across the country. So far, two have been dismissed outright and four others have been partially dismissed, and no plaintiffs have won any damages, he said.