The U.S. Justice Department told a federal appeals court here yesterday that a District of Columbia plan for hiring more black firefighters is unconstitutional because it denies white applicants an equal opportunity for the jobs.

Justice lawyers, in a brief filed with the court, repeated the Reagan administration's position that quotas that benefit blacks discriminate against whites.

The fight over the hiring plan, approved by a U.S. District Court judge in April, is part of a nationwide effort by the Justice Department's Civil Rights Division to eliminate racial hiring quotas in the public sector.

The brief said the D.C. Fire Department plan cannot pass constitutional muster and violates federal civil rights law because those blacks who would benefit from the hiring goals have not suffered personally from discrimination, while equally qualified white applicants would be denied jobs unfairly.

The Reagan administration maintains that all job applicants must be treated equally according to ability and regardless of race.

The Justice Department is appealing Judge Charles R. Richey's approval April 26 of a city affirmative action plan for hiring 127 firefighters, nearly two-thirds of whom would be black. While Richey allowed the city to proceed with its hiring plans because of current manpower shortages, he asked the city to file another hiring and promotion plan.

City officials said the plan was necessary to remedy the "grossly disproportionate hiring" of minorities over the last 25 years. Richey reluctantly approved the plan as a "minimally acceptable" effort to overcome past discrimination, but he rejected an affirmative action scheme for promotions within the fire department.

Justice criticized the hiring plan as "a substitute for a nondiscriminatory selection procedure" and argued that Richey is prohibited from granting relief to job applicants "other than identified victims of discrimination."

Goverment lawyers maintain that the hiring plan's preference for black applicants "is not a permissible, let alone compelling, government interest" and that "there is simply nothing remedial -- let alone equitable -- about a hiring plan that grants preferential treatment to individuals whose personal right to nondiscriminatory treatment has not been violated."

The court has not yet scheduled oral arguments in the case.