Two rival police organizations here are embroiled in a new union battle that could determine which group will represent some 4,000 sergeants and officers in the D.C. Metropolitan Police Department.

The controversy involves the International Brotherhood of Police Officers (IBPO), the current bargaining agent for District police, and the Police Association of D.C., which is challenging the IBPO for the right to represent the police in future contract negotiations with the city.

Spokesmen, for the police association said yesterday they ahve gathered about 1,400 signatures on petitions they expect to file Thursday with the D.C. Office of Labor Relations asking that a representation election be held between the two organizations. Officials said that 1,215 signatures - those of 30 per cent of the proposed bargaining unit - are needed to call an election.

Such an election would probably be held in May before the May 31 expiration of a current three-year contract for police officers.

The IBPO and the police association were rivals once before in a three-way representation election held in 1974. It was the first time District police had ever unionized, and the IBPO was eventually chosen as the bargaining agent following a run-off election against the association.

Located at 2139 Wisconsin Ave. NW, the IBPO union has about 2,900 members compared to about 700 members in the police Park Police and is trying to become the bargaining agent for the Executive Protective Service.

But D.C. police officer Gary Hankins, who campaigned for the IBPO three years ago but has since joined the rival association, said yesterday his group hopes to become the new bargaining agent for the force by putting more emphasis on service to union members.

"I don't think the IBPO is concerned with the welfare of the officers. Its efforts are directed towards protecting itself as a national organization and expanding."

The police association has represented members of the police force for 75 years, primarily as a social and lobbying organization. It has never been the bargaining agent since police officers did not have collective bargaining rights until three years ago.

The IBPO, as the union of the police force, has more members than any of nealy 10 other police organizations or societies to which the officers can belong. Many police have dual membership in more than one association.

Supporters of the police association have complained that the IBPO has not lived up to the promises it made when it first won the right to represent members of the force. They argue that the police union local is dominated by the national office here.

But officers for both the national office of the IBPO and Local 442, which represents District police, stressed yesterday that the local "runs its own affairs" and has worked hard to negotiate a good contract for the police and to look after their interests.

"The police association labels all these items (various contract demands) as promises never delivered, but we never promised," said Alan Whitney, executive vice president for IBPO. "We did publish a list of objectives, and we told the officers that some would be easier than others to get because some items require changes in legislation."

According to Whitney, the city took the position during the last contract negotiations that several items of discussion presented by the union "were nonnegotiably." The IBPO, he said, recently took the issue to an outside arbitrator designated by the federal mediation service.

He has ruled, Whiteny said, that many of the union's demands are not negotiable because they would require legislative changes that would have to be approved by Congress.

There are three important exceptions to this, however, according to Whitney. He said the arbitrator ruled the union may now negotiate night differentials (extra pay for work done between 6 p.m. and 6 a.m.), overtime pay for the time officers spend in roll call and premium pay for work done on Sundays. Average annual pay for officers about $14,000.

Legal representation for officers charged with job-related offenses is another item of controversy between the two groups. The IOBPO has four full-time lawyers and says it can better represent legal interests of members. The police association says that while this may have been true in the past, the association now has also retained counsel to help with any job-related legal problems an officer might encounter.

The police association has recently moved to new headquarters at 608 Massachusetts Ave. NE where it is setting up a gym, bar, kitchen and dormitories for officers who spend all day in court and need to sleep before going back on duty.

"I'm not going to do the same thing," said Larry Melton, vice president of the IBPO local, who noted that so many other police organizations have established social gathering places for police that "there are no where places to drink in this town. I'd rather spend the money on lawyers."