The Justice Department urged yesterday that court-ordered busing be ended in elementary schools that have complied with desegregation orders, even if doing so increases racial segregation in some schools.

In a brief filed in a Virginia case, Assistant Attorney General William Bradford Reynolds said a return to neighborhood schools would increase parental involvement and stop whites from fleeing the public school system, thus providing "more stable and lasting desegregation in the public schools as a whole."

"It is time in Norfolk -- as in many, many other school districts around the country that have sustained for years good-faith compliance with court-ordered desegregation plans -- to restore to the local authorities full responsibility for running their public schools. Our filing in this case urges that result," he said.

Hundreds of court-ordered school busing plans have been implemented nationwide on a case-by-case basis since the Supreme Court ruled in 1954 that segregated schools are unconstitutional.

The Reagan administration has consistently refused to support busing plans in new desegregation cases. But until yesterday, it had not addressed the question of ending court-ordered busing after a school system satisfactorily desegregates.

The Justice Department brief was filed in the 4th U.S. Circuit Court of Appeals, where black Norfolk schoolchildren are challenging a U.S. District Court's ruling that the Norfolk school board can abolish its court-ordered busing plan. The lower court found that the school system, which is 60 percent black, has been in compliance with the Constitution and court desegregation orders for more than 13 years and showed good-faith compliance.

According to the Justice Department brief, abolition of busing in Norfolk would result in 10 schools more than 90 percent black, one school more than 70 percent white and 26 more equally balanced schools. Currently no school is more than 90 percent black, one school is 73 percent white and the rest have racial ratios of approximately 60-40 and 50-50, according to school board attorney J.A. Stalnaker.

Lawyers for the plaintiffs, who want to keep the court-ordered school busing plan, said they were dismayed by the brief.

"This is an attempt to overrule the Brown Brown v. Board of Education Supreme Court decision, clear and simple," said Henry L. Marsh III, former mayor of Richmond and a lawyer for the black children. "It is tragic that the U.S. government will support a return to racial segregation in 1981. It is tragic indeed."

Marsh said he disliked the Justice Department's and school board's position that abolishing school busing will keep the system from becoming segregated again by encouraging whites to stay in the system. "They're forcing blacks to return to a segregated system because of white flight, because of hostility to blacks," he said.

The new school board plan of returning to neighborhood schools would give children the option of transferring to a more racially balanced school, the Justice Department brief states.

Children who stay in racially isolated neighborhood schools can engage in a "parental involvement program especially designed for students from lower socioeconomic areas," the brief says. "Given these undisputed facts, it is simply not possible to conclude that the board's plan is designed to segregate students on the basis of race."

The brief states that the percentage of whites in the system fell from about 55 percent to about 41 percent as whites fled after school busing was implemented in 1971.

Those numbers were disputed by Napoleon Williams of the NAACP Legal Defense Fund in New York and a lawyer for the black students. Williams said that many whites fled the school system during the three years after busing was first implemented, but that since 1981 the number of whites in the schools has increased by 184 and the number of blacks decreased by 700.