Federal agencies are dusting off seldom-used layoff procedures in anticipation of deep jobs cuts -- which could affect as many as 60,000 U.S. workers -- that President Reagan is expected to propose in his first budget to Congress next week.

Some key government personnel officials say they have been tipped to ready contingency plans for cutbacks in the neighborhood of 5 to 6 percent. Few departments and operations expect to be exempt. They have also been advised to get acquainted with just-issued reduction-in-force (RIF) procedures relating to the elite Senior Executive Service.

Reagan has already frozen federal hiring and canceled job promises made after Nov. 5. His total freeze replaced a partial hiring cutback imposed last year by president Carter. Carter's freeze reduced federal employment by 23,000 jobs in its first few months.

But the number of U.S. workers began to climb again last September. The relationship of the Reagan freeze to the coming job cutback order is unclear, as is congressional reaction to slashing agency programs. But officials say that even if the current job freeze remains in place for months it would not prevent layoffs in federal agencies should Congress approve Reagan's new austerity proposals.

The severity of th cutbacks would depend on the job base the Reagan administration uses, and the timetable it sets for planned reductions.

Reagan administration officals are planning a major revision of the budget that Carter sent to Congress just days before he left office. Normally federal agencies could turn to their key political appointees -- and the Office of Personnel Management -- to help fight off deep cuts in jobs and programs. Those key officials turn to special pressure groups and friends in Congress to block many of the cuts before they are put in the budget. But many of the top and midlevel jobs in government have not yet been filled, perhaps by design. And the Office of Personnel Management, which normally supplies key pro-federal worker advice to the White House, is still operating with an acting director and deputy director.

On Feb. 7 Reagan sent a toughly worded memo to department and agency heads outlining spending and tax reduction plans he will propose in his Feb. 18 budget. The memo said that within the following nine days the Office of Management and Budget would be "consulting agencies about additional reductions. . . ." It told agency heads that if they had "better ways to achieve reductions" they were to get their ideas to the powerful OMB "within 48 hours" In other words Reagan left no room for argument against cuts, and very little time for new cabinet appointees or their career staffs to come up with alternatives to slashes in the works from the OMB.

The Washington area, which has 362,000 federal workers, could be hard hit by the job cuts, according to knowledgeable personnel directors.

Federal agencies have the authority to offer early retirement to employes hit by RIFs and -- since the civil service reform act -- major reorganizations. But they may not be as generous with the early-out retirements this time around.

The General Accounting Office recently reported to Congress that the early-out authority had been badly abused in the past by federal agencies that often granted retirement at age 50 (with 20 years of service) or at any age after 25 years' service for what GAO said were phony RIF's and dubious reorganizations. Although federal workers retiring early take a significant reduction in pension benefits, early retirement on immediate annuity has added millions of dollars to the cost of the federal retirement program, GAO said.

In a normal RIF, the least senior workers are the first fired or bumped out of jobs. But RIFs can be tailored to make sure certain people are forced out while other jobs are protected.

"We've been asked a lot about RIF procedures by budget examiners," one federal personnel chief said, "and you don't have to be a genius to figure out what that means!" He said that Defense and the National Aerounautics and Space Administration have considerable experience running RIFs, but that few of the "domestic" agencies, like Commerce, Labor, Justice, Health and Human Services and Interior "know very much about RIFing."