A federal appellate court has cleared the way for the Department of Housing and Urban Development to fire, demote or reassign 140 employes, as of Monday, because of what the agency says are staffing imbalances and program changes.

The U.S. Court of Appeals for the District on Wednesday reversed an order issued last month by U.S. District Court Judge June L. Green that enjoined HUD from conducting a scheduled reduction-in-force in its headquarters here until next year. While supporting some arguments challenging the RIF, the appeals court ruled that there was nothing in the legislative history of the agency's budget proceedings in Congress to ban HUD's staffing reorganization.

As a result of the RIF, initially ordered to take effect Oct. 31, a HUD official said that 35 employes will lose their jobs. Another 28 employes will have their dismissals temporarily delayed, including 12 agency secretaries slated for new assignments. The order also will result in the downgrading of 57 employes and the reassignment of 48 others.

There are approximately 4,000 employes working in HUD headquarters.

"We've never had a RIF in HUD headquarters, although we have transferred some people to the field," said Judith Tardy, HUD's assistant secretary for administration. She said a strict hiring freeze in force since February 1980 increased staffing imbalances.

Tardy said HUD wants to conduct a RIF because of skills imbalances--too many people in jobs that are no longer needed--and program changes and because of technological improvements, including automated accounting operations, that cut the number of employes needed.

She acknowledged that RIF regulations have a negative effect on minorities and women, who may not have seniority and veterans' preference protections. But she said the actual percentage of minorities and women in the agency before and after the RIF changed only slightly, from 43.8 percent minorities and 50.12 percent women before the RIF to 43.7 percent minorities and 50.11 percent women afterward.

Ernest Parker, president of the American Federation of Government Employees, Local 476, which represents the HUD workers, said the union intends to keep fighting the RIFs and is considering an appeal to the U.S. Supreme Court. Parker accused the agency of using this latest court order to conduct the staff shake up in violation of RIF regulations and the union's contract.

He also protested HUD's contention at a news conference yesterday that it is 533 employes over its personnel ceiling. Actually, that figure is HUD's staffing request to the Office of Management and Budget, he said, adding that the agency was 539 under its personnel ceiling as of Oct. 31.