Every government worker would have a choice of pension plans under legislation the Senate Governmental Affairs Committee is due to take up today.

The bill, sponsored by committee Chairman William V. Roth (R-Del.) and Sen. Ted Stevens (R-Alaska), gives feds hired before 1984 the choice of staying in the current retirement plan or transferring into one of two new options proposed for the 300,000 workers hired since the end of 1983.

New employes, who are under Social Security, could chose only between the two new options proposed.

Both new plans base retirement benefits on Social Security, a modified civil service pension package and income from tax-deferred investment programs.

People remaining in the current retirement system could still retire at age 55 after 30 years service on unreduced benefits and get cost-of-living raises fully indexed to inflation. While employed, they would continue to put 7 percent of their salaries into the civil service retirement fund and pay only the Medicare portion of Social Security.

Under the new plans, workers would pay the full Social Security tax of 7.05 percent.

In one option, workers would contribute nothing toward civil service but would have to work until age 62 to get full benefits.

The other would allow employes to contribute 1.3 percent of their salaries to the federal pension fund and retire on unreduced benefits at age 55 after 30 years with the government.

Both new options provide smaller civil service benefits than the current civil service program, which bases pensions on length of service and the employes' highest three-year salary average.

The option offering the lowest civil service benefit allows employes to put up to 10 percent of their salaries (with the government adding an additional 5 percent) into tax-deferred investments.

The second option offers a higher civil service benefit but reduces employe tax-deferred contributions to 6 percent and the government share to 3 percent.

Both would base future benefits on the employes' highest five-year average salary and give cost-of-living adjustments 2 percent lower than the actual inflation rate.

Benefits of persons already retired from government or for employes who stay in the current retirement program would not be changed.

Congress has until the end of the year to set up some kind of supplemental retirement program for new workers who are covered by Social Security.

House Democrats are expected to propose a supplemental retirement package that provides better civil service benefits (and protects the existing retirement age) after the Senate completes action on its proposal.

There is still lots of congressional negotiating to be done, but time is running short.