U.S. District Court Judge Aubrey T. Robinson Jr. ordered the government yesterday to hold a two-week open season enrollment period beginning Dec. 7 so that the 9.2 million people covered by the federal employe health benefit (FEBH) insurance program can shop around for better or cheaper health insurance coverage in 1982.

Robinson's ruling also ordered the Office of Personnel Management to restore benefits and higher premiums proposed by plans that OPM had rejected earlier this summer.

The ruling stunned OPM managers of the program, which covers more than a million people in metropolitan Washington. OPM officials said they would seek a stay of the order while appealing it to the U.S. Court of Appeals.

OPM Director Donald J. Devine, who is in Rome attending an international personnel conference, issued a statement saying the decision "threatens the integrity and perhaps even the survival" of the insurance program.

The judge's order, Devine said, will have the effect of raising premiums -- split 60-40 by the government and its employes -- in some plans. He also said that Blue Cross-Blue Shield, which covers half of all federal employes, will "probably now drop out" of the federal program. Blue Cross-Blue Shield officials could not be reached for comment. Earlier they had said that they might have to drop out unless they were allowed to cut mental health benefits.

Earlier this month OPM said it was postponing indefinitely the open season enrollment period, which originally was scheduled to run from mid-November to early December. Yesterday's successful appeal was filed by the National Treasury Employees Union, which was joined by other unions and health plans seeking an immediate open season.