The Senate Governmental Affairs Committee yesterday approved a bill to increase federal pay and sent the measure to an uncertain future on the Senate floor.

The legislation, approved by a 7 to 1 vote, for the first time would allow the federal government to pay differing salaries to federal workers doing the same jobs in different localities, depending on local market rates.

The Senate committee's bill is less than half as expensive as similar House legislation reported out of the Post Office and Civil Service Committee last week. Even so, it carries a $3.8 billion price tag over five years at a time when the government is facing a budget deficit of $218.5 billion for the current fiscal year.

Committee Chairman John Glenn (D-Ohio) said the bill was essential to "deal fairly with the Civil Service. . . . I have heard from every department secretary, every single one," he said. "Their programs are adversely affected" because of their inability to pay competitive salaries.

Glenn said federal salaries have fallen 28.6 percent behind comparable wages in the private sector.

"As the pay gap grows, the ability of the federal government to recruit and retain employees becomes a more difficult and complex task," said Sen. William V. Roth Jr. (R-Del.).

Mindful of the deficit, however, Roth said he would offer an amendment on the Senate floor that would enable the president to hold down or defer wage increases in cases of "national emergency or serious economic conditions affecting the general welfare."

Neither the House nor Senate bill will be taken up by the full chamber until after the August recess.

The House Post Office and Civil Service Committee approved a $9.5 billion bill last week on a 19 to 4 vote.

The Senate committee bill would grant federal workers an annual increase equal to the employment cost index for wages and salaries in white collar occupations, not including sales.

The president would have the authority to reduce the figure by 0.5 percent in the event of national emergency or serious economic conditions affecting the general welfare.

In addition, employees in high wage areas where federal salaries lag behind the going rate for comparable work would be entitled to "locality" wage increases in addition to the universal raise.

The major differences between the House and Senate pay bills are in the amounts of money paid to federal workers in the high-cost areas and in the discretion given the president to hold down wage increases.

The House bill calls for closing the 28.6 percent pay gap in the high-wage areas of the nation within 10 years. The Senate bill calls for "beginning the process of closing the pay gap by establishing a form of locality pay to make the government more competitive in areas where the pay gap is greatest."

Sen. Carl M. Levin (D-Mich) cast the dissenting vote on the Senate committee bill yesterday. He said his principal concern is over whether locality pay can be awarded equitably.

Under the Senate bill, the locality pay areas would be established by the executive branch with the advice of a Federal Pay Council dominated by representatives of employee labor organizations.

Wages in the "locality" areas would be surveyed and increases to keep federal employees' salaries comparable to workers in similar local jobs could be granted by the president.

Levin said he was concerned over whether the concept could "work equitably in practice. What about people on the other side of the line?" he said.