Hundreds of Washington area federal workers could be laid off in coming months unless Congress comes up with supplemental salary money to get their agencies through the fiscal year that ends in September.

Agencies with problems include the Interstate Commerce Commission, the Consumer Product Safety Commission, the National Aeronautics and Space Administration and the National Science Foundation.

Athough it is too early to panic, a number of agencies -- including Agriculture and the General Services Administration -- are dusting off RIF (reduction in force) plans that may be put in effect this fall if Congress makes budget cuts or agencies go ahead with plans to turn work over to private contractors.

During the first 2 1/2 years of the Reagan administration, about 2,900 of the area's 350,000 civil servants were riffed (a government term for layoffs) for economy reasons.

Many thousands were downgraded or moved to other jobs because of the ripple effect of the RIFs, producing a serious case of job jitters in many agencies. Many of the cuts in domestic agencies were offset by stepped-up civilian hiring in defense agencies.

Friday afternoon, ICC employes -- 600 here and about 300 in the field -- got word that they may be furloughed for up to 26 days starting next month unless Congress comes up with extra money to meet the payroll. The ICC has been shrinking through attrition, but it is $4 million short of salary money for this fiscal year.

The ICC had the option of firing 32 employes or furloughing everybody one day a week for 26 weeks to cut costs.

The Consumer Product Safety Commission has alerted Congress that it may have to RIF about seven employes this year. The Goddard Space Center is talking about a RIF involving 13 employes, and the National Science Foundation is looking for two people to lay off.

The General Services Administration recently revised competitive rules that would be used to see who goes and who stays if the agency's budget is cut or, as anticipated, if the agency contracts out more work.

Some of the RIFs could be avoided if agencies freeze or slow their hiring or if Congress comes to the rescue. But if agency budgets are cut -- and Congress will finish its first budget resolution sometime in May or early June -- the area will be in for another round of job jitters.