Transportation Secretary Drew Lewis said yesterday the Reagan administration is concerned about the embattled American auto industry but is not rushing forward with help in any of the industry's three major problem areas -- imports, regulation or financial assistance.

In his first news conference as secretary, Lewis said he will head a Cabinet-level committee to review the auto industry's troubles and expects to meet next week with officials of the auto companies and the United Auto Workers. The unemployment and financial losses in the auto industry are "the single most pressing problem in transportation," he said.

"We are challenged by burensome tax rates, bloated federal spending, high interest rates and overbearing federal regulations that are causing havoc not only in the auto industry but other industries, as well," Lewis said.

But in response to questions, he said that DOT has no plans to abolish legislation requiring installation of passive-restraint belts in cars and "would not walk away" from safety and environmental regulations in general.

The Reagan administration intends to honor the federal government's commitment to aid Chrysler Corp., the industry's prime invalid, Lewis said, indicating that the new administration will authoize $400 millon in loan guarantees tentatively approved in the last full day of the Carter administration, provided Chrysler's newfinancing plan is approved by the company's union employes, lenders and suppliers.

But the administration does not intend to "subsidize" industry, he added.

"If we can see Chrysler surviving we'll be supportive. If we can't, we'll be looking for other solutions."

Continued high unemployment in the industry is inevitable, Lewis said, suggesting that further wage concessions by the UAW will be necessary.

Asked about the auto industry's repeated requests for limits on Japanese auto imports, Lewis said this problem, too, will be considered but that "free trade" is the basic policy of the Reagan administration and that President Reagan has no intention now of asking for import limits on Japanese autos, he added.

Lewis said that as part of the administration's effort to control spending, DOT will review current commitments to mass transit and interstate highway construction projects to see whether any should be delayed. He also favors reduction in federal subsidies fro the operation of mass transit systems.

Meanwhile, during a Senate hearing yesterday, representatives of the nation's Big Three automakers said they wanted Congress to modify a number of automobile safety, pollution-control and fuel-economy regulations to help them focus more on management and research and give them more resources for retooling to small, fuel-efficient cars.

However, Sen. John C. Danforth (R-Mo.) who chaired the hearing of the Senate Commerce, Science and Transportation subcommittee on surface transportation, didn't appear to be ready to buy their argument. For example, Danforth said consumers conceivably could save $300 to $400 on a car if some regulations were eliminated. But he asked, "Isn't that a drop in the bucket when cars are selling at a minimum of $5,000? We're going to save a pittance."

Herbert L. Misch, a Ford Motor Co. vice president, said the saying "is a tremendous amount to us. We need help. We need every bit of help we can get."

"It's like gettng a fig leaf when you have to live in the North Pole," Danforth said.