Congressional investigators are combing federal retirement records to see if some officials have used liberal programs to retire early or "buy out" senior-level employes so they can fill jobs with their own people.

Results of the investigation, to be made public within the next few weeks, could lead to legislation tightening up federal disability retirement rules and early-out retirement. Money saves as a result of changes in the two costly programs could serve to block attempts to save money on other federal retirement programs by eliminating one of the two annual cost-of-living raises federal and military retirees receive.

General Accounting Office auditors, at the request of Sen. David Pryor (D-Ark.), are taking an especially close look at recent retirements from the Office of Personnel Management and Merit Systems Protection Board. The two agencies were set up when President Carter's civil service reforms abolished the old Civil Service Commission.

The OPM was the first agency to take advantage of new legislation -- in the Civil Service Reform Act -- that allows employes to retire as early as age 44 on immediate annuities because their agency is undergoing reorganization.

Congressional investigators also are intrigued by the fact that one of every three federal workers who retire does so because of disability. An employe certified as "totally" disabled gets a minimum lifetime annuity equivalent to 40 percent of his/her highest three-year average salary.Most persons retired on disability are certified by the government as being totally disabled.

There is growing feeling in Congress that the disability retirement system has been inadequately policed an interpreted, and that it is often used by agencies to force -- with financial sweeteners and job pressure -- people to leave.

Under new early-out retirement programs, agencies undergoing reorganizations or layoffs may offer retirement on immediate annuity to anyone with 25 years of service (regardless of age), or to persons with 20 years of service who are at least age 50. There is a 2 percent reduction in annuity for each year the individual is under age 55. For persons who retire and take other jobs, that early-out can be a bonanza. It also benefits agency heads who want to clean out their senior-level workforce.

The Office of Personnel Management must approve agency early-out requests. OPM was the first agency to use the new early-out authority, and a number of longtime employes who were veterans of its predecessor agency -- the Civil Service Commission -- elected to get out.

Investigators have also been checking individual cases, stemming from allegations from employes, retirees and unions that the early-out has been used by some officials to get out of government, and then come back as consultants or private contractors.

The typical civil servant -- who is taxpayer as well as contributor to the retirement fund -- could benefit in several ways if rules are tightened.

Congressional budget committees in recent years have considered saving millions of dollars in federal pension programs by eliminating the March and September cost-of-living adjustments retirees get, in favor of a single increase each July. Backers of the twice yearly adjustment plan argued, successfully so far, that they can make savings in other areas. If they can, the two cost-of-living raises can be maintained. If not, Congress may again work up legislation to eliminate one of them.