A "work-to-rule" protest was announced yesterday by a newly formed union that represents physicians employed by the Group Health Association, the largest health maintenance organization in the Washington area.

Union officials said the "work-to-rule" action would not endanger or inconvenience any Group Health patients. "We do not intend to inconvenience the patient," Dr. Norman Lieberman, the union's president, said last night. "We don't have a fight with the patient."

One of the major effects of the "work-to-rule" protest, Lieberman said, would be an increase in the number of participants in the GHA plan who are given medical treatment at outside hospitals, rather than at GHA's own clinics.

GHA is a prepaid group medical practice association that provides medical care to about 108,000 members in the Washington area, many of them federal government employes. The union, known as GHA Physicians' Association, was formed after a 53-to-16 victory in an election Jan. 4. It represents the nearly 100 full- and part-time physicians employed by GHA.

The union's action was designed to protest what appeared to be a temporary halt in negotiations over a contract for the GHA physicians. According to union and GHA officials, the talks were broken off about 3:30 a.m. yesterday.

Lieberman and Tom Gagliardo, the union's lawyer, blamed GHA officials for interrupting the negotiations. Harold Wool, GHA's president, accused the union of setting an "arbitrary" deadline -- yesterday -- for completing the negotiations and said a federal mediator was needed to help conclude the bargaining.

Gilbert S. McCutcheon, a mediator for the Federal Mediation and Conciliation Service, said last night that he had not yet determined when another negotiating session should be scheduled.