The Justice Department has agreed to drop a hiring discrimination suit against the Prince George's County Police Department next year if the county continues its recent efforts to recruit minority police officers.

In a motion to be filed in Baltimore's U.S. District Court today, the federal agency states that the county's affirmative action policies over the last two years have had a "dramatic effect" on the hiring of minority policemen.

The motion notes that since the suit was filed in June 1976 about 40 percent of the police recruits in Prince George's have been blacks or women. If that trend continues, the Justice Department says, the suit will be dropped on July 2, 1979.

The Justice Department's action apparently brings to an end a bitter dispute between federal and county officials, which saw the county filing a counter-suit and refusing for nearly two years to negotiate with Justice attorneys. Several times during that period, one side accused the other of "playing to the press."

But bickering continued yesterday after the tentative settlement was announced.

"In my view, the Justice Department is acknowledging in this pleading that the county would most likely win the suit if we came to trial on this issue," said County Attorney James C. Chapin, "I think Justice has recognized in hindsight that this suit should never have been filed."

Justice Department lawyer Maimon Schwartzchild disputed Chapin's claim.

"We don't share that judgment," said Schwartzchild. "That best way to respond to that statement (that the suit should not have been filed is to point out these facts: between 1972 and 1974, 4 percent of the police recruits were black; between 1974 and 1976, 15 percent were blacks or women; since the lawsuit was filed in 1976, 40 percent of the recruits have been blacks or women."

The tentative dismissal motion gives the Justice Department the right to continue the suit if county officials fail to adhere to several guidelines. It states that the county must make "a good faith effort, consistent with the efforts over the past three years," to increase minority representation on the police force at and above the entry level of police officer.

Chapin said the county would continue its minority recruitment efforts on the entry level. "But I'm not sure we can legally recruit black officers above that level," he added. "That might result in another reverse discrimination suit. Right now, we only recruit at the entry level!"

Chapin said the lawsuit cost the county "a lot of unnecessary time and expense." He said he had five attorneys working on the case for various periods of time. "It was a very technique, complex case," said Chapin. "We had to hire experts on retainer to review our hiring procedures to see if they were proper. They (the experts) concluded they were."

The county attorney said the Police Department had begun a concerted minority recruitment effort before the Justice Department filed the suit.

County police Col. Vincent duCellier, the department's administrative and personnel officer, detailed that effort in an interview yesterday.

"The first thing we did was open up our personnel shop to make the hours more convenient. We interviewed applicants at night and on weekends. Then we instituted walk-in tests so people wouldn't have to wait two or three months to see if they could get past the first stage of recruitment.

"Then we went out into the community and established contacts with career placement officers at military installations and black colleges, as far away as South Carolina and California. But most important, we took efforts to make minorities know we really wanted them. If they needed temporary housing, we arranged it. If they needed temporary transportation, we provided it."

The apparent resolution of the Prince George's suit comes at a time when two other Maryland counties are under pressure from federal agencies to increase the minority representation on county work forces. The Justice Department filed a suit against Baltimore county yesterday, accusing it of "systematically discriminating against blacks and women" in all departments. In Montgomery County, officials are challenging a federal order to set black hiring quotas in the Police Department.