Mayor Marion Barry has introduced emergency legislation to bar the city police union from representing prison guards because of potential "conflict" if District police were again called in to replace striking guards, as happened in the 1981 D.C. Jail strike.

The bill, which could be enacted as early as next week, would short-circuit a current organizing drive by the Fraternal Order of Police, which represents 3,300 D.C. police employes and is seeking to replace the union representing the 2,000 corrections officers and other workers at the D.C. Department of Corrections.

"We think that it places a police union in a conflict of interest if they were needed in a situation in the Corrections Department but belonged to the same union," Donald H. Weinberg, the city government's chief labor negotiator, said yesterday.

If enacted, the law would be one of very few in the country to ban police unions from prisons, according to FOP lawyer Robert Deso, who accused the mayor yesterday of trying to circumvent rulings by the D.C. Public Employee Relations Board (PERB), which rejected the city's argument in 1982 and again this year.

"Our position is that we obey the law. We do not strike," Deso said. "We do not think it would be a threat to public safety" to have police manning prison jobs held by fellow union members. Strikes by any public employes are illegal in the District.

Labor relations have been turbulent in the city prison system, where complaints of dangerous working conditions, poor morale, and low pay have prompted an effort by the FOP to replace the long-established prison union, the American Federation of Government Employees.

Both the FOP and the AFGE will oppose the bill at a meeting Monday of the City Council's Government Operations Committee, a union spokesman said yesterday.

"We see this as the mayor's attempt to protect a friendly union, the AFGE, from a sure defeat at the hands of the FOP," said Gary Hankins, chairman of FOP's labor committee.

An AFGE spokesman said, "We are in favor of a vote. We believe the workers should decide this question."

While FOP is trying to replace AFGE at Lorton reformatory and the D.C. Jail, AFGE in turn is attempting to replace FOP as the police union. The emergency law would also prevent that effort.

The city is seeking to enact rules similar to the so-called "plant-guard rule" that has developed under the National Labor Relations Board, which has ruled that private-sector employers have a legitimate interest in preventing factory guards from belonging to the same union as production workers because guards could not necessarily be relied upon to stop vandalism or violence by their fellow union members.

The District's 1980 Merit Personnel Act gave D.C. employes the right to join any legitimate labor organization, and PERB, which administers the law, rejected the city's effort in 1982 to limit that rule for police and prisons.

"A strike of Corrections Department employes would obviously pose serious problems for the city," PERB said, "but there is nothing in the record above the level of assumption and speculation to indicate that FOP representation would pose additional difficulties or interfere with efforts to maintain public safety."

PERB again rejected the argument last August but reheard the case at the city's request last month. The board is currently considering the issue, but the law would render that decision moot, Weinberg said.