Prince George's County school officials and the NAACP have reached an interim agreement that will allow the school system to continue current staffing levels at 14 predominantly black schools, even though black activists have argued that the staffing formula could jeopardize the integrity of the county's school desegregation program.

The agreement, stemming from NAACP complaints that the school system had failed to provide enough teachers at the predominantly black schools, resolves the first major dispute between activists and school officials over the county's court-ordered desegregation plan.

NAACP representatives said yesterday that, for now, they will go along with Superintendent John A. Murphy's plans to open two new schools for talented and gifted children this fall and that they will temporarily accept a staffing formula at the so-called Milliken elementary schools.

The group had earlier alleged that the school system had reneged on promises to limit the program for the gifted and talented and to reduce class sizes at the Milliken schools to one teacher for every 20 students. The county average for elementary schools is one teacher for every 27 students.

Alvin Thornton, a key player in the agreement and chairman of the committee monitoring the desegregation effort, said yesterday that the pact will allow "flexibility, given the practical difficulties the school system faces."

The agreement was accepted in the face of a possible court order that would have given the school system discretion to continue as it had, Thornton said, noting that such rulings are typical during the early phases of desegregation plans.

"We have not spelled out what will happen a year from now," said George Mernick, the attorney for the NAACP. "If we're not happy, we're going to make a fuss."

School officials had said that adhering to a strict classroom size of 20 students, as the NAACP had sought, would be costly and pose severe logistical problems.

Murphy said in an interview, "I never saw it as a battle, so I'm not sitting here claiming victory."

Sources close to the settlement said that the two sides sought a quick end to the dispute because it overshadowed recent achievements of the once-criticized school system and, more important, threatened public support of the entire school desegregation plan.

The Milliken schools are those deemed too difficult to desegregate because of their distance from mostly white communities. Under an agreement stemming from a longstanding desegregation suit against the school system, educators and black leaders agreed to pour extra staff and resources into these schools in light of the legal segregation.

In a two-page letter, Board of Education attorney Paul M. Nussbaum said the system will try to assure that "instructional groups . . . in key academic areas" are limited to 20 students, particularly in schools that have not made significant academic improvements since the Milliken program was introduced two years ago.

Under the agreement, school officials plan to open programs in September at Longfields and Oakcrest elementary schools for talented and gifted pupils, despite the NAACP's initial opposition.

Black leaders, citing their belief that white students disproportionately benefit from the special classes, had said that the earlier agreement banned further expansion of the programs.