Willard Wirtz, chairman of the D.C. Public Employee Relations Board, resigned his post last week, and officials with the Fraternal Order of Police (FOP) charged yesterday that Wirtz left because of a conflict with Mayor Marion Barry's administration over a disputed police contract that is now in the courts.

Wirtz, a labor secretary during the Kennedy and Johnson administrations, has been replaced as chairman on an interim basis by William H. Rumsey, who was serving as a member of the PERB and previously had held two cabinet-level posts with the city.

District officials denied that Wirtz left because of a clash with Barry's administration. City Administrator Thomas Downs said the move stemmed from Wirtz's desire to "spend a little more time at his place in West Virginia."

Wirtz would not say yesterday why he resigned, but said Downs' explanation was incorrect.

"While appreciating the friendliness of these explanations, my only reaction is that they have nothing to do with the facts," he said. "The administration has these facts and it is appropriate to leave their handling up to them."

Gary Hankins, chairman of the FOP's labor committee, said Wirtz had not cooperated with Barry's efforts to have the panel overturn an arbitrator's ruling that for the first time would have put police salaries above parity with firefighters' pay.

"In a conversation with me, the mayor indicated to me that he felt that the reconstituted employe relations board might be more receptive to his way of thinking," Hankins said. The FOP leader also criticized the selection of Rumsey, charging that he was a close associate of the mayor who would be "more inclined to Barry's point of view and less than neutral."

Rumsey dismissed Hankins' statement, saying, "I have never voted anything but my conscience."

Wirtz, who is among the original appointees to the board, was nearing the end of a second three-year term when he resigned. Wirtz said he had voted to support the arbitration panel's finding in favor of the police union. Rumsey declined to say how he voted in the dispute.

The fight over the police contract centers on the board's role in the first District labor dispute decided by binding arbitration under the city's relatively new labor law. An arbitration panel ruled last May in favor of the police officers union.

The following month, the Barry administration asked the board to overturn the findings. After the board declined to do so, the city filed suit against the board and the FOP in D.C. Superior Court seeking to to reverse the board's decision and force it to reconsider the city's appeal of the arbitration.

Hankins said the D.C. government, in appealing the panel's finding and filing suit, had exceeded the bounds of the D.C. labor law and was "abusing the negotiation process." Said Hankins, "My feeling is that because Mr. Wirtz and the board behind him collectively and repeatedly enforced the labor law, he drew the ire of the mayor."

Barry has said that he opposes the police contract because it allows a "dangerous and expensive" precedent that will cost the city millions of dollars.

Donald H. Weinberg, director of the D.C. Office of Labor Relations and Collective Bargaining, said that if the court rules for the city, the case will go back to the board, opening the way for new actions by the panel under Rumsey's leadership.

However, Weinberg said, if the court finds for the defendants, the administration likely would submit the contract to the D.C. City Council for final review. A two-thirds council vote would be necessary to reject the contract. Many council members have said they support the police officers in the dispute.