The federal civil service --

2.8 million people with an average age of 41 who earn $80 billion a year -- would shrink, almost overnight, if Congress approves an unprecedented early-out plan that would allow 700,000 senior employes to retire between July 1 and Dec. 31.

Under the bill, by Sens. William V. Roth Jr. (R-Del.) and Ted Stevens (R-Alaska), the government would temporarily waive normal age and service requirements. The purpose is to induce older workers to leave so that younger employes won't be axed later on because of pending budget cuts.

Right now about 250,000 feds are eligible to retire. The Roth-Stevens bill would make it possible for about one in every four government workers to qualify for an immediate pension.

The earliest most federal employes can retire under current rules is at age 55 after 30 years. The Roth-Stevens bill would permit early-outs starting in July for anyone with 25 years of service, at age 50 with at least 20 years' service, at age 55 with 15 years' or at age 57 after five years' service. Annuities would be reduced 2 percent for each year the retiree is under the age of 55.

The Congressional Budget Office estimates that 65,000 employes might take advantage of an early retirement offer. That number could be much higher if Congress also enacts a tax reform bill that takes away a post-retirement tax benefit now available to federal workers and other employes who help finance their own pensions. If such a change took place, it could provoke a massive retirement stampede by workers seeking to beat the deadline.

Backers of the Roth-Stevens plan say it is a humane proposal, modeled after early-outs offered in industry, to reduce the work force without having to fire younger employes with the least seniority.

Opponents of the bill, including many federal labor unions and professional groups, say its passage could wreck many federal programs and services by tempting some of the government's best workers to leave and then not allowing agencies to replace them. No Holiday Furloughs

The Agriculture Department has dropped plans to furlough 9,000 employes of the Food Safety and Inspection Service on Memorial Day, Independence Day and Labor Day. FSIS originally proposed the furlough to meet budget cuts by reducing payroll costs without disrupting service to meat and poultry processing plants.

Reps. Mike Barnes (D-Md.) and Vic Fazio (D-Calif.) asked the General Accounting Office for a ruling on the holiday furlough plan. GAO's decision issued last week said furloughing employes only on holidays is contrary to federal personnel rules. People

Kimberly Parker has joined the American Postal Workers Union to be special legislative assistant to president Moe Biller. Parker was with the House Budget Committee staff for two years and was a lobbyist for the American Federation of Government Employees and the National Treasury Employees Union.

The Institute of Internal Auditors D.C. chapter has given its person-of-the-year award to Lawrence N. Rapley of the International Bank for Reconstruction and Development.

OPEDA, Agriculture's professional employe organization, is having an open house Wednesday at 1301 New York Ave. NW. Those being honored include John Triplaar, longtime agricultural counselor for the Netherlands Embassy.

National Science Foundation's Robert S. Cutler has been given a Fulbright scholarship to study technology transfer in Japan.