General Motors Corp. yesterday claimed an engineering breakthrough in development of the controversial airbag and said it would offer the safety option in its large 1982 models.

Two months ago GM cited possible injury to small children from the inflatable passive restraints in announcing a delay in their introduction. The airbags have been the subject of heated discussion on Capitol Hill, where opponents are seeking to overturn a law that will force automakers to start offering automatic passive restraints in 1982 models.

But a GM spokesman confirmed yesterday that company officials have informed Transportation Secretary Neil Goldschmidt and his top highway safety aide, Joan Claybrook, that the company will have airbags in 1982 cars, barring "unforeseen developments."

"Evidently we have worked out the child-restraint problems," the spokesman said. "And we plan to offer the fully inflatable system as an option on the 1982 large-sized cars."

He added, however, that plans to offer a driver-only inflatable airbag system in some 1981 models have been discontinued because of problems with development. "We are concentrating on getting the full system in 1982 cars," he said.

GM car buyers will have the option of automatic seatbelts on some 1981 models, he said.

"We're delighted," Claybrook said yesterday. "This is a breakthrough for automotive safety. This shows that Gm has employed its engineering talent and resources for the benefit of the public."

Consumer advocate Ralph Nader, who has long championed the airbag, said, "Although GM is seven years behind its own earlier deadline for installing life-saving airbags in automobiles, the company's decision . . . should provoke other auto companies to similar performance on behalf of millions of motorists, as well as greatly diminish the anti-airbag forces in the Congress."

In 1970 GM said in papers filed with the Department of Transportation that it would have airbags in all cars by the fall of 1974. Instead, it offered its experimental program.

Federal standards mandate that automakers install passive restraint systems beginning with large 1982 models. Mid-sized cars and small cars must follow suit in 1983 and 1984, respectively.

Although the standard does not specify the type of passive system to be offered, it appears that only the airbag will suffice in some cars.

In others, the passive belt system, which involves a seat and shoulder belt that automatically close on the occupant when the car door is shut, will meet the requirements.

Both Ford Motor Co. and the Chrysler Corp. yesterday reiterated that they will comply with the federal standards. Ford intends to offer airbags. Chrysler, however, is seeking to exempt its 1982 large cars because they will be phased out of production.

Although GM essentially pioneered development of airbags, it has not been convinced that the public will approve of the system. When GM offered the airbag option on some 1974-76 models, it claimed fewer than 5,000 people a year bought them.

But newly released marketing studies by the auto giant as recently as february 1979 show its customers say they overwhelmingly prefer airbags to passive restraint belts, even with a price tag as high as $360.

Rep. John D. Dingell (D-Mich.) has led congressional efforts to prevent DOT from enforcing passive restraint requirements. Next week, he plans to offer an amendment to the Dot authorization bill that would further that goal.

GM has not taken a public stand on Dingell's efforts.