A congressional subcommittee is conducting a preliminary investigation into allegations that Delta Airlines and three large Utah travel agencies are breaking antitrust laws - charges the companies have already repeatedly denied.

Earlier this fall, the U.S. Department of Transportation received similar complaints from 22 smaller Utah travel agencies. The so-called "big three" consists of Morris/Ask Mr. Foster, Murdock Travel and Beehive-Bonneville Travel.The smaller agencies recently wrote Rep. Howard Nielson, R-Utah, saying they feel little action has been taken on their complaint, said Ken Salaets, a staff member of the House Subcommittee on Government Activities and Transportation, on which Nielson is the ranking minority member.

Salaets said Nielson turned the travel agencies' letter over to him for preliminary investigation. He said he feels it raises several issues that may lead to Congressional hearings next year.

The smaller agencies claim Delta unfairly gave the big three a Delta computer reservation system and provided exclusive bulk or tour-based fares. The smaller agencies said the arrangements are anti-competitive, and brought them a 30- to 50-percent reduction in revenues.

Salaets said he has found that federal agencies may have been slow to look into the complaints to this point, partly because Washington is in a "lame duck" period where action is slow awaiting results of the presidential election.

Also, he said, the Justice Department indicated insufficient evidence exists at this point to allow prosecution to proceed on any sort of price-fixing or antitrust laws.

But Salaets said the situation does raise questions about the cost to travel at airports that are heavily dominated by one airline.

"It isn't just a Utah issue with Delta. Others include Memphis where Northwestern has 80 percent of the business, and TWA in St. Louis," he said.

Salaets said the subcommittee may wish to hold hearings on the effect that deregulation has had on the costs and services at such airports because of the complaint.

Salaets said he will continue to look into the complaint before Congress reconvenes in January, and may travel to Utah to conduct interviews on the situation. He said he will prepare a report for Nielson, who will decide whether to raise it at the subcommittee level.

Meanwhile, officials of the big three travel agencies have denied any wrongdoing. Richard Frendt, president of Morris/Ask Mr. Foster, has gone on record saying, "We do not apologize for offering superior savings and service to our customers."

The agency, which is Utah's largest, said their smaller competitors are unwilling to "meet the challenges of deregulation."