The budget President Reagan will send Congress shortly will call for stepped-up efforts to turn over hundreds of operations that now employ as many as one in five federal civil servants to the private sector.

Previous "privatization" efforts have met with mixed results. Federal employment has grown under Reagan. But the new political obsession with deficit reduction could force an election-year Congress to consider farming out traditional federal services to firms that -- at least initially -- say they can do it better, faster and cheaper. Private contractors can often make low-bid job estimates because they pay workers less, recognize fewer costly holidays or offer workers bare-bones (or no) retirement benefits, or count on turnover to keep them from having long-term pension costs.

December's budget compromise, engineered largely by Office of Management and Budget chief James C. Miller III, put the U.S. Postal Service -- with congressional approval -- in the position of cutting services and closing offices even as it went ahead with plans to raise stamp prices. That's the sort of thing that could make politicians rethink laws that now prevent anyone but a government letter carrier from delivering things to your mailbox.

Through the years a number of private firms -- with mixed success -- have taken over jobs previously reserved for government employees. One of the most visible here is the growing number of private security guards at federal agencies, jobs that were once reserved for military veterans hired by the General Services Administration. For some time open-season health insurance services for government retirees have been handled by a private firm in the Midwest.

Federal areas that private firms are eager to expand in, or take over for both profit and control reasons, include:

Managing national parks and other visitor-oriented operations now largely run by Uncle Sam.

Allowing various delivery services and stamp sales now controlled by the Postal Service.

Providing mailing, information and clerical services for U.S. agencies.

Running computer operations for places such as the Internal Revenue Service, Veterans Administration and Social Security Administration.

Processing claims for retirement and other benefits now handled by the Office of Personnel Management.

Support services ranging from security to laundry and aircraft and vehicle maintenance at federal agencies and military installations.People

David Sanasack has left the Federal Managers Association to become vice president of the International Management Group. He had been executive director of the managers association since 1986.

Peter Hickman, longtime public affairs officer with the U.S. Information Agency, General Services Administration and Agency for International Development, is the new chief executive of Interpress 77, a Spanish-based firm that produces magazine supplements for newspapers. Job Mart

Customs Service is looking for general engineers, GS 12 through 14 ($32,567 to $38,727 to start), and a GS 12/13 aerospace engineer. Call Linda Robinson at 634-5065. Army needs a GS 9 inventory management specialist. Call Gloria Chandler at 692-5412. Social Security in Manassas needs a clerk-typist, GS 2 through 4. Call Sandy Johnson at (703) 369-3113.