The Teamsters union and large trucking companies told members of Congress yesterday that administration legislation to further deregulate trucking would cause hardship for employes and companies and create unsafe operations.

But Transportation Secretary Elizabeth Hanford Dole called the legislation "a major part of the overall administration objective to remove inefficient regulatory restraints wherever they are found."

Many shipping groups also supported further deregulation of the trucking industry.

The contrasting views came in a Senate Commerce subcommittee hearing, the first step in what is expected to be a protracted debate. Subcommittee Chairman Bob Packwood (R-Ore.) is an unabashed fan of deregulation. Committee Chairman John C. Danforth (R-Mo.), however, has questions.

This was underlined when Packwood lectured Dole at length on the wonders of deregulation, then said: "I don't know why I'm lecturing you." Danforth jumped in, saying, "I know who you're lecturing." Laughter broke out in the hearing room, packed with lobbyists and lawyers.

The administration's bill essentially would shut down the part of the Interstate Commerce Commission that still regulates interstate trucking. The Motor Carrier Act of 1980 significantly reduced the ICC's authority, but it still is required to approve "entry" for new companies and to file tariffs, or rates.

As a practical matter, almost all applications for entry into the industry are approved automatically and tariffs, once filed, are shelved to serve no futher function. Dole called the procedure a huge "paper chase."

Danforth asked whether a new deregulation bill would not unnecessarily disrupt an industry that already has been substantially deregulated and has endured a recession and new taxes in the recent past.

"Aren't we keeping this industry too off-balance?" he asked. "Shouldn't we give it some time to settle down?"

Paul R. Locigno, the Teamsters' director of government affairs, said of Dole's testimony: "Not one word was mentioned about the workers and their families."

Locigno estimated that 40,000 to 50,000 workers lost their jobs as a result of many trucking firms going bankrupt in the early 1980s. The administration attributes most of the bankruptcies to the recession and to overcapacity.

The proposed legislation does not include labor-protection provisions. Packwood asked Locigno whether the Teamsters would support deregulation "if you had adequate labor protection."

"I seriously doubt it," Locigno replied.

Thomas J. Donahue, president and chief executive officer of the American Trucking Associations, said that further deregulation would stimulate price wars and accelerate the growth of a few huge firms, among other things.

Both Donahue and Teamster witnesses said that a proliferation of unregulated, underfinanced small firms has resulted in an increase in unsafe operations on the highways.