Federal and postal workers who retire early and take lump-sum pension payments would be spared a 10 percent penalty tax under legislation approved by the Senate Finance Committee.

For the typical federal retiree a lump-sum payment could be worth around $30,000, although in the case of long-service, high-paid workers those payments can be $70,000 or more.

Under current law, when federal employes retire, they can elect to receive lump-sum payments equal to all the money -- typically 7 percent of their lifetime salary -- they contributed to their retirement program. The lifetime civil service annuities of those who take the lump-sum option are reduced from 8 percent to 12 percent.

Most of the lump-sum payment is considered taxable income, meaning that individuals who take it have that amount added to any other income they receive in the same year. In addition to the regular tax on the payments, the Tax Reform Act of 1986 also subjected the lump-sum payments of persons who retired before age 55 to an additional 10 percent penalty tax.

But the Senate committee has approved correcting language, introduced by Sen. Spark M. Matsunaga (D-Hawaii), that would not impose the tax on employes unless they retire before age 50. Those who retire after their 50th birthday would not be subject to the added tax.

Typical retirement age in government is 55 after 30 years of service, 60 after 20 years' service or 62 after five years' service. But thousands of employes in stressful jobs -- air traffic controllers, firefighters, law enforcement personnel and foreign service personnel -- are either encouraged or required to retire at age 50.

For those employes, plus regular workers who leave early because of agency layoffs, the 10 percent penalty tax has been an extra harsh -- and many believe -- unfair burden.

Still up in the air is whether the Matsunaga proposal, if approved, would be retroactive to provide relief for employes who already have retired and been forced to pay the 10 percent penalty.Job Mart

Government Printing Office is looking for an assistant public printer (human resources), Grade 17 or 18, $72,500 a year. Applicants must have civil service status. Call Karen Urchasko at 275-2880.

Federal Energy Regulatory Commission needs a secretary- steno, GS 6. Call 357-5410.

Selective Service System in Georgetown wants a personnel management specialist, GS 9 through 12, and a secretary (typing), GS 5/6. Call 724-0435.

Marine Corps needs a GS 12 computer programmer analyst; GM (merit pay) 15 supervisory computer specialist; Wage Grade 9 plumber, and Wage Grade 8 maintenance worker. Call Gloria B. Thomas at 640-2048.

Department of Education has an opening for a GM 14 supervisory personnel staffing specialist. Call 472-2980.Publications

The Federal Employees Almanac is taking orders for its 1988 edition. It contains updated information on federal pay and pensions, job and travel rulings, and on the old and new federal pension plans. Don Mace, formerly of The Federal Times, and Joseph Young, longtime civil service columnist for The Washington Star, edit the almanac. Copies are $3.95 and can be ordered from the Almanac, P.O. Box 7528, Falls Church, Va. 22046-1428.