A sworn statement by a Justice Department lawyer, released over the government's objections, appears to directly contradict the basis for the department's challenge of a minority hiring plan in Birmingham, Ala.

The Justice Department approved a consent decree four years ago that allows Birmingham officials to increase minority representation in city jobs by hiring or promoting blacks and women over more-qualified white candidates. But the department has since reentered the case on the side of white city employes, arguing that the city is violating the decree by discriminating against whites.

In a highly unusual deposition released last week, Richard J. Ritter, the Justice Department attorney who negotiated and signed the 1981 consent decree, described the agreement in the same terms city official are using in their defense.

Civil rights attorneys said the deposition shows the Justice Department's current arguments in the case to be a "fraud" and a "baseless fabrication."

A spokesman for the department said he failed to see any contradictions in its case.

The issue surfaced when Assistant Attorney General William Bradford Reynolds, who took office shortly after the 1981 decree was signed, joined several suits filed by white city employes passed over for promotions.

Reynolds, who opposes race-conscious remedies, accused Mayor Richard Arrington Jr. and the city of illegally favoring blacks over "demonstrably better qualified" whites.

But city officials say they are simply living up to the hiring goals in the 1981 decree.

Ritter said in the deposition that "we certainly anticipated" that Birmingham would give preference to some black and women candidates.

He said he expected "that there would be occasions when the city would resort to selecting qualified blacks" even if "it believed there was a demonstrably better qualified white applicant available."

"It was my understanding that the city would be permitted to select a qualified black or female applicant, who the city was satisfied was qualified, in preference to a demonstrably qualified white . . . if the city in good faith believed that kind of selection was necessary to meet goal obligations," Ritter said.

Ritter said the decree provided Birmingham with a valid defense for favoring minorities. He also said the city was "required" to hire qualified blacks to meet hiring goals if the differences among candidates was marginal.

Stephen J. Spitz, an attorney with the Lawyers Committee for Civil Rights Under Law, which is representing Birmingham, said the deposition shows that Justice Department officials "have reneged on their contractual obligations to enforce the decree they signed.

"They have compounded it by lying; that's the only word that's appropriate," Spitz said. "They tried to hide this from the public because they're going to be embarrassed by it. They've changed their position and they don't want to admit they've changed their position."

Justice Department spokesman Terry H. Eastland, accusing civil rights lawyers of "trying the case in the newspapers," said he could not comment on the deposition because it might not be admitted as evidence in the case.

"We don't think there's anything in Mr. Ritter's testimony that is incompatible with the arguments we've been making," Eastland said. "The decree does not allow the current practices of the city, whereby demonstrably less qualified blacks were promoted over demonstrably more qualified whites on the basis of race."

The Justice Department tried to block the Ritter deposition and then to keep it under court seal on grounds that it involved internal discussions and attorney-client privilege. U.S. District Court Judge Sam C. Pointer Jr., who unsealed the statement, has criticized the department for making "contrary" and "inconsistent" arguments in the case. Birmingham is a majority black city with a long history of discrimination.

About 13.5 percent of the city's entry-level firemen are black; in 1973, only two of the fire department's 640 employes were black.

"Blacks were excluded for a long time here from the police and fire departments," said Jim Alexander, an attorney for the city. Without minority hiring goals, he said, "it would be generations before you could make any meaningful changes in the complexion of the work force."