The government says it will not conduct a formal safety investigation of Jeep CJ vehicles, rejecting consumer activists' contention that design flaws make the vehicles prone to roll over.

"There is no reasonable likelihood that further investigation would lead the agency to determine that a safety-related defect exists in these vehicles," said Jerry R. Curry, administrator of the National Highway Traffic Safety Administration.The agency also found no evidence that the vehicles' manufacturer, American Motors Corp., withheld documents from the government in a deliberate cover-up, Curry said. Chrysler Corp. acquired AMC in 1987.

The safety probe was requested by Public Citizen, the Center for Auto Safety and the Institute for Injury Reduction. Such investigations can lead to recalls.

They asked the agency to investigate what their petition described as "the undue, unnecessary and defective propensity of the CJ vehicles to roll over."

The groups accused AMC of knowing the vehicles' suspension system was defective and their roll bar assembly inadequate.

Curry said an exhaustive inquiry showed the Jeep CJ's likelihood to roll over was "slightly higher" than the average for all utility vehicles. But the CJ "does not stand out from its peers to an extent that warrants further investigation," he said.

Deaths in CJ rollover accidents totaled 116 in 1989, said Michael Brownlee, the agency's associate administrator for enforcement.