Most federal employes retiring any time after Jan. 1, 1983, will be eligible for full Medicare coverage when they reach age 65, even if they pay or have paid into the system a relatively short time.

Federal workers can retire with as little as five years' service if they are age 62. To get Medicare benefits, government workers who retire in 1983 will need to have only eight years of federal service, or combined federal and private sector service (in a job covered by Social Security).

Thanks to a grandfathering provision put in by Congress, government employes will be blanketed into Medicare even if all their prior 1983 work time of at least eight years was in government where they did not have to pay the Social Security tax. Most other American workers who reach 62 next year will have had to pay the 6.7 percent Social Security/Medicare tax for at least eight years to qualify for benefits.

Federal employes will pay only the 1.3 percent Medicare portion of the Social Security tax. They will not be eligible for other Social Security benefits unless they got coverage for non-federal work.

Congress did not intend to make current, longtime federal employes meet the normal service requirements for Medicare coverage. And the Health Care and Financing Administration has ruled that any employe on the payroll for one day in January and eligible for federal retirement will qualify for Medicare by using his or her federal service (and private sector work time if necessary) to meet the required number of "quarters," which equals eight years.

For example, if you retire next year with five years of federal service, you can combine that time with any private sector service in a Social Security-covered job (time needed would be only three years) to qualify for Medicare.

As time goes by, however, the number of "quarters" that people must work under Social Security is due to increase gradually. For instance, persons who turn 62 in 1987 will have to have nine years of Social Security employment to qualify for its benefits and Medicare. Federal employes will have to meet the same criteria of nine years of federal and/or private service, except they will pay only the Medicare tax, and get only Medicare benefits.

HCFA next week will issue information on Medicare coverage to federal agencies that they can pass on to about-to-retire workers. In January, HCFA will put out a special pamphlet, Medicare for Federal Employes, that explains what they must pay for Medicare, and how long they will have to pay it to qualify.

The Office of Personnel Management also is expected to put out a fact sheet for feds. Meantime, Medicare coverage (and the tax) is coming, and if you are eligible for federal retirement next year, odds are that your federal service time, plus any time in private industry, will qualify you for the Medicare benefit. Stay tuned.