Washington area employers predict a stable job outlook for the next three months, although federal employers for the first time in recent history say they plan to reduce the number of workers in the District, according to a survey released yesterday.

The survey results are in concert with Carter administration efforts to reduce the size of the federal bureaucracy and shift some federal workers out of the Washington area, an Office of Management and Budget official said.

The survey, published quarterly by Manpower, Inc., the world's largest temporary-help firm, said that the trend toward less federal employment in the District follows "a slowdown pattern noted in (District) public hiring three months ago."

A manpower spokesman said he noted no decrease in federal employment in other cities surveyed, but that 19 percent of local and primarily federal employers in the District said they plan to decrease employment. Twelve percent said they will increase employment, and 69 percent said they expect no change in the number of workers in their agencies.

Since coming to office, President Carter has pledged to reduce permanent, full-time federal positions by 20,000, and he has instituted at least two hiring freezes, the OMB officials said.

Current federal employment levels are constrained by ceilings on each agency's budget, and executive branch employment ceilings have been instituted by the Civil Service Reform Act of 1978, the offical added.

The result of Carter's initiatives is just showing up now because of a time lag, the OMB officials said.

"It's probably becoming more apparent now," the official said. Carter's actions didn't "show up in real terms until a year or two later."

From January 1977 until last September, the number of full-time, permanent employes in the executive branch nationwide, excluding postal workers, was reduced by 19,400, from 1,911,900 to 1,892,500, the OMB official said. The official said he had no figures on the number of employes moved out of the Washington area.