A D.C. Superior Court Judge ruled yesterday that the city government may begin deducting union dues or equivalent fees from the paychecks of about 3,000 police officers, whether or not they are members of the International Brotherhood of Police Officers.

The action is the latest round in a bitter internal fight between that union and the rival Fraternal Order of Police, which is attempting to oust the IBPO as the bargaining agent for city policemen. The FOB wanted no deductions until settlement of a legal challenge it filed against the contract negotiated last month between the city and the IBPO.

Judge Tim Murphy lifted a temporary order issued last week that stopped the city from collecting those dues after a lawyer for the IBPO's nationaloffice pledged that the union would refund any money collected under the new contract if the FOP is successful in its challenge.

Murphy said that since the two unions were disputing the contract itself before the city's Public Employe Relations Board, and since it appeared that there was now some guarantee that the dues would be repaid to non-union members if the IBPO lost, he would, in interests of home rule, not intervene in the case until the city board had a chance to act on the matter.

About 2,200 officers are members of the IBPO, but about 800 have resigned recently because of dissatisfaction with the new contract, which provides cash bonuses in its first two years and a 7 to 9 percent pay increase in the third year. The new contract also permits automatic union dues or fee deductions from paychecks of officers who are not now members of the IBPO.

The FOP has filed an unfair labor practice complaint with the employe relations board, alleging the city acted in concert with the IBPO to ensure that no rival unoin could challenge the IBPO's right to represent the officers.