Administration officials yesterday reaffirmed their support for far-reaching legislation to reduce regulation of the trucking industry, but a key senator predicted that this year's measure will not go as far as they, or he, want.

"It will be a move toward deregulation, but not as much a move as I would like to see . . .," Sen. Bob Packwood (R-Ore.), ranking minority member of the Senate Commerce Committee said.

His comments were made to a well-attended day-long symposium on truck regulatory reform on Capitol Hill arranged by a broad coalition of trade association, companies and consumer groups that support change in trucking regulation.

Parkwood called "baloney" the argument being used by the regulated trucking industry that small communities will lose all trucking services if regulation is reduced. He said small towns that have lost air service since the airline deregulation measure are experiencing "a transitory shift" as commuter airlines grow and mid-sized airplanes suitable for small town service become available.

"You'll be surprised how many companies will find they can make a profit serving small towns," he said. "Don't let that argument be used against any kind of trucking deregulation."

Packwood's comments came amid strong endorsements for significant changes in trucking regulation from Neil Goldschmidt, Transportation Secretary; Alfred E. Kahn, advisor to the president on inflation; and Esther Peterson, special assistant to the president for consumer affairs.

"We consider this legislation to be a high-priority item because it tackles two significant problems that are facing the nation right now; energy and the economy," Goldschmidt said.

Proponents of trucking deregulation argue that a more competitive industry would result in lower shipping rates -- and therefore lower consumer prices -- for food products and other commodities hauled by trucks, more fuel-efficient industries, new services to small towns, and new opportunities for the small businessman to enter the industry.

Legislation sponsored jointly by the Carter Administration and Sen. Edward M. Kennedy (D-Mass.) also won plaudits from Thomas A. Trantum, one of three new members of the Interstate commerce Commission, the agency that regulates trucking.

Trantum, who studied the trucking industry for eight years as a security analyst before joining the ICC, said regulation as now practiced by the agency requires him to sit in judgment on conflicts between shippers and trucking firms, as well as decide who should be allowed to carry what products where, along what routes, and how much money they should earn doing it. "I'm good, but I'm not that good," he said.