ANCHORAGE, Alaska — Alaska’s wolf-killing program to boost moose and caribou numbers is facing a new legal challenge.

Two conservation groups filed a lawsuit in Superior Court alleging that the program, in which more than 550 wolves have been killed, is based on faulty science and violates state law.

Defenders of Wildlife and the Alaska Wildlife Alliance asked the court last week to halt the program authorized in 2003 by the state Board of Game .A similar court challenge launched by the Connecticut-based group Friends of Animals was not successful in putting an end to the program.

But in that case, Superior Court Judge Sharon Gleason had ruled that the Game Board had not followed its own rules in approving the programs and had not considered all alternatives besides aerial killing. The Game Board responded with new regulations that satisfied the legal shortcomings and resurrected aerial killing of wolves in all five areas.

A spokesman for the Alaska Department of Fish and Game, Bruce Bartley, said the agency is more confident of the legality of the program since making the required changes as a result of the Friends of Animals case.

“All of our actions, no matter what they are, are subject to judicial review, and we understand that, and we do the best job we can with the best information we have available to develop scientifically sound programs in whatever we do,” Mr. Bartley said. “We are confident in the science of it.”

The state maintains that predator control is a well-managed program to provide more game in areas where rural hunters say wolves and bears are killing too many moose and caribou calves, leaving them with too few to hunt and eat.

Critics say it is aimed at wiping out more than 80% of wolves in a large swath of Alaska — about the size of Wyoming — to benefit mostly urban hunters.

“It is largely being done for people coming out of Anchorage who want an easy time getting moose or caribou,” senior director of field conservation programs for Defenders of Wildlife in Washington, D.C., Caroline Kennedy, said Tuesday.

The president of Defenders of Wildlife, Rodger Schlickeisen, said the game board lacks accurate information on caribou and moose numbers to develop a science-based plan.

“The Board of Game ignored well-established, solid science when they set up the aerial wolf-killing and bear-killing plans,” he said.

The Alaska Department of Fish and Game claims that predators kill more than 80% of the moose and caribou that die during an average year, while humans kill less than 10%. The aim of their program is to temporarily reduce wolf numbers but not to permanently eliminate them in any area, the department says.

Under the program, the state issues permits so that pilots and gunners can either shoot wolves from the air or land first and then shoot them. Numbers of wolves to be killed this winter have not been set yet. The program also allows for the killing of black bears.

“We feel they haven’t begun to meet the criteria necessary to justify the level of killing they are attempting,” the director of the Anchorage-based Alaska Wildlife Alliance, John Toppenberg, said.

Mr. Toppenberg said the Board of Game does not have the science to back up the program.

“Our position is that this state is best served by having an intact ecosystem with a healthy predator-prey balance. That kind of eradication has nothing to do with balance,” he said.