The District government has been found guilty of unfair labor practices for unilaterally cutting off dental and optical benefits for about 5,000 police officers and firefighters, an action that increased tensions during stalemated contract talks that appear headed for arbitration for the first time.

The D.C. Public Employee Relations Board, which supervises labor relations between the city and its 30,000 workers, said city officials engaged in a "patently coercive" act by canceling insurance coverage Sept. 30, when two-year labor contracts expired with the Fraternal Order of Police and the International Association of Firefighters.

The employe board ordered the city to comply within seven days with its ruling, which was issued last Tuesday. The board said the city's actions violated longstanding provisions of labor law that bar employers from changing wages or working conditions while contracts are being renegotiated.

"If employers were entitled to make unilateral changes . . . it would invite unrestrained coercive action by employers and inevitable retaliatory and disruptive action by unions," said the strongly worded six-page ruling.

"That is [the employe relations board's] opinion. Not ours," Donald H. Weinberg, D.C. director of labor relations, said yesterday. He said the city government will meet with the unions this week, as ordered, but that it has not decided whether to appeal the ruling.

On Sept. 30, when contracts expired with seven unions representing more than 18,000 employes, the city cut off its $2.5 million annual contribution to dental-optical coverage. The action was strongly denounced by the unions, which said the termination threat was an attempt by Weinberg to pressure them into accepting what they called a paltry contract offer.

Weinberg said then that the city had been willing to continue benefits, "but there were things we wanted" in exchange, which he would not specify. The benefits were reinstated for five other unions last month when the city settled with those unions representing 13,000 workers. But police officers and firefighters remain without coverage while their talks continue.

The October contract settlement -- with the American Federation of State, County, and Municipal Employees, the American Federation of Government Employees, and three smaller unions -- provides 3 and 4 percent annual pay increases, but the police and fire unions are seeking raises of roughly 10 percent yearly, according to the city.

Giving higher raises to police and firefighters would greatly complicate the city's labor picture, sources said, because of a so-called "me-too" understanding with the five unions that they would receive larger increases if the city gave more to the FOP or the firefighters.

In a separate action, the FOP has filed a petition with the employe board alleging that the city is refusing to bargain in good faith and asking the board to declare an impasse. A declaration of impasse would lead to naming a mediator and, if no settlement is reached, a panel of arbitrators. Arbitration has not been used in the four years since the District has had full collective bargaining with its employes.

City officials have said they hope to avoid arbitration because it would empower arbitrators to make decisions that could cost the city millions of dollars.

The police union's 13-page petition said that despite seven months of meetings, "No issues have been resolved through direct negotiations except for ground rules." The union blamed Weinberg for the impasse, saying that he "erupted violently" and used abusive language at various sessions, and that he has refused to meet on various occasions.

"The city has refused to meet with us and repeatedly frustrated our efforts to negotiate. They've dragged this out in a ridiculous fashion and delayed us interminably with trivia," Fraternal Order of Police lawyer and chief negotiatior George B. Driesen said yesterday.

Weinberg disputed the union's contentions, saying he did not believe the talks were at impasse. "We have only had three real bargaining sessions and I don't think after only three sessions you can have impasse," he said. He also said the characterization of his behavior was exaggerated.

Weinberg laid blame on the police union, saying, "From the beginning, the union has had its sights set on arbitration, and not meaningful bargaining. They must think they can get more from an arbitrator than from a bargainer." He said talks are proceeding with the firefighters union.

Weinberg said bargaining with the police union was suspended recently because of upcoming elections ordered by the employe board to determine which union will represent 3,600 police and 2,000 Department of Corrections employes. AFGE, the police union and the Teamsters are competing in those elections, and Weinberg said the city does not believe that "meaningful bargaining" can occur because of the chance that new unions could replace incumbents and demand new contract talks.

Driesen said the city's position runs counter to federal labor law and the city's rules, which say that pending elections "will not require withdrawal from bargaining."