The House Ways and Means Committee today may decide whether to merge the federal civil service retirement program with Social Security.

Vote counters say that all 12 Republican members of the Committee, and as many as seven Democrats favor "universal coverage" under social security. That would include integrating the federal retirement system, and those pension plans of state-local government and nonprofit organizations with Social Security. If that coalition of Republicans and Democrats hold together, it would be enough to win merger in the committee which has 35 members.

Backers of the pension merger plan say that it would not cut benefits of federal workers - whose retirement program is much more generous than Social Security. They say also that the idea behind universal coverage is not to avoid temporarily a Social Security tax increase by getting federal civil service retirement funds into the program.

They say a single basic national retirement insurance program would be more fair to the taxpayers, and stop federal workers who retire early and then put in minimum time and money contributions until they also become eligible for Social Security coverage.

Federal and postal unions fear that "universal coverage" will mean an eventual watering down of the government pension program. It is a staff retirement system not a minimum insurance program like Social Security, which was designed to augment other retirement income.

Opponents of the merger will try first to block it outright. If that fails they have other amendments to offer that they hope will guarantee the financial integrity of the civil service fund, which pays more generous benefits because workers pay more for them.