The Reagan administration yesterday took the first step toward killing the controvesial federal regulation requiring new cars to be equipped with air bags or automatic seat belts starting with the 1982 models.

Transportation Secretary Drew Lewis proposed a one-year delay in implementation of the first phase of the "passive-restraint standard," saying the delay "would give us time to review the overall regulation."

The decision, which has the blessing of the White House, still must go through regulatory procedures -- such as publication in the Federal Register and a period for public comment -- before being implemented.

Noting that auto sales "are seriously stunted by inflation and high interest rates," Lewis said forcing automakers to install the costly safety gear, "would aggravate those problems."

During the campaign President Reagan promised to reconsider the air bag rule and several transition advisors have urged throwing out the long-debated safety measure.

President Carter's auto safety chief, Joan Claybrook, made air bags her top priority and spent much of her term heading off congressional efforts to stall the requirement or kill it.

Air bags would save the lives of 9,000 crash victims a year and prevent an estimated 65,000 serious injuries, backers of the measure claimed. They contended it would save the public $4.3 billion a year by cutting medical treatment costs and lowering auto accident insurance premiums.

Lewis commented little about the safety impact of delaying the regulation, saying, "there is a need to act with the utmost care to achieve the greatest measure of safety and to minimize possible burdens both to the purchaser and the maker of new cars."

The passive restraint rule now in effect requires all full-size cars to have air bags or automatic seat belts starting with the 1982 models that go on sale next September. Midsize cars would have to have passive restraint a year later, and small cars would be covered when the 1984 models go on sale in September 1983.

Lewis yesterday issued a proposed amendment to that rule, delaying the large-car requirement until September 1982, when the 1983 models go on sale. The decision effectively puts the whole issue on hold.

Starting the air bag requirement in big cars doesn't make sense, the Transportation secretary said, because full-size models "are already the safest of all."

Lewis also said starting with big cars "may be unintentionally discriminatory against the domestic manufacturers. The Japanese manufacturers do not in fact build any large cars.

"The rule now on the books requires American manufacturers to invest capital to meet the terms of the standard several year before foreign firms must comply," he said. "The last thing we want to do is give the foreign automakers a future advantage in our marketplace."

Lewis noted that when the rule was first adopted big cars dominated the market and air bags seemed to be preferred over some form of automatic seat belts. Now the public is demanding small cars, which have a much worse crash safety record and presumably a greater need for occupant protection. Automatic belts, which cost about $25 compared with a $100-to-$200 air bag, already are being sold on some small cars.

Office of Management and Budget Director David Stockman was a leading foe of air bags when he served as a congressman from Michigan. Stockman called for rescinding the rule in his transition memo urging the president take quick action to avoid "an economic Dunkirk."

Stockman estimated killing air bags would save the auto industry $300 million to $600 million over three years. The Carter administration's Regulatory Council, in a report issued last month, put the capital cost of the regulation at $100 million.