The government will open bidding this month on its order for 5,000 airbag-equipped cars, a first-of-a-kind fleet purchase that some federal officials hope will lead to widespread acceptance of airbags as auto safety devices.

However, Ford Motor Co. apparently will be the only major automaker to show up at the auction.

Chysler Corp. and General Motors Corp. so far "have responded negatively" to initial government invitations to participate in the bidding, said Leonard Lann, a National Highway Traffic and Safety Administration official. Other domestic and foreign automakers have shown little interest in the project, he said.

If Ford remains the only bidder at the end of August, the General Services Administration--the federal purchasing agency working with NHTSA on the airbag project--will seek a sole-source contract with the company, Lann said.

"We're basically interested in establishing a market for airbag-equipped cars," Lann said.

GM and Chrysler, the nation's first and third largest automakers, have said the government's proposed program is too small to justify production costs.

But Helen Petrauskas, Ford's vice president of safety engineering, said the fleet proposed by the government would be large enough to test the benefits and shortcomings of airbag-equipped cars.

Ford, should it get the order for the 1985-model cars the NHTSA and GSA wants, probably would supply a fleet of airbag-fitted Tempos, Ford's newest, front-wheel-drive compact cars, according to Ford officials.

In October 1981, NHTSA halted its own efforts to require the use of airbags or automatically closing seatbelts, but a federal court has overturned that action and an appeal is pending.