Congressional Republicans seeking ways to reduce the deficit are considering a 5 percent pay cut for members of Congress and other top government officials, a pay freeze for other federal workers and a two-thirds reduction in inflation adjustments for all major benefit programs, including Social Security and government pensions.

While no decisions have been made, proposals for limits on government salaries and retirement benefits appeared to be gaining momentum as Congress continued groping for alternatives to President Reagan's budget.

Sen. Jesse Helms (R-N.C.) suggested a 5 percent cut for senior government officials at a meeting Wednesday of the Steering Committee, an informal group of conservative Republican senators that he heads. Although some Senate leaders dismissed the proposal as unlikely to survive, Helms said he had gotten nothing but positive responses from his colleagues.

Sen. Ted Stevens (R-Alaska), who has championed the cause of federal pay increases in Congress, told reporters that he was "not too happy" about proposals to cut pay for top executives only a year after Congress finally agreed to raise their long-frozen salaries.

But he said civilian government pay may have to be frozen at all levels next year and military pay limited to an increase of 3 to 5 percent. Reagan has proposed pay increases of 5 percent for civilian workers and 8 percent for the military.

A pay freeze is on the "working sheet" of possible deficit reductions that Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) has forwarded to the White House. Baker was described yesterday by an aide as "intrigued" as well by the idea of a pay cut for top government officials.

Helms said he has yet to firm up details of his pay cut proposal, including precisely whose pay would be cut. He said it would generally include members of Congress and "high-level executive branch" employes, including the president unless there are constitutional problems with doing so.

In any case, Helms said he would expect Reagan to agree voluntarily to a salary cut. High-ranking military officials and congressional employes would also have their pay cut.

While the savings would be "insignificant," Helms said, a cut would be a "demonstration of good faith" by the government at its highest levels that "we're serious about balancing the budget and cutting deficits."

Added Helms: "We have the perception of throwing 20 widows out in the snow every day and protecting ourselves with tax breaks . . . . It's time to reestablish some credibility with the people."

Talk of a two-thirds reduction in cost-of-living increases for Social Security and other benefit programs emerged again in the Senate yesterday in the face of continued White House rejection of any change in Social Security. There had been discussion earlier of total elimination of the inflation adjustment for two years, and the new talk appeared aimed at trying to strike a compromise, or at least a talking point for negotiations.

Baker said in a speech Wednesday night in Cincinnati that all benefit entitlement programs, including Social Security, had to be explored for savings. But he told reporters yesterday that he was "not at all optimistic" that cost-of-living increases could be scaled back this year.

Baker also said that, while the focus of the budget-rewriting effort has shifted to the House, Senate Republicans were close enough to a consensus to act if the House fails.

And, even as some Democrats at a House leadership meeting were expressing misgivings about a proposal from House Budget Committee Chairman James R. Jones (D-Okla.) to put Reagan's budget to a vote if Reagan won't compromise, Baker said he had no problems with the idea.

"It's all right with me," said Baker, rejecting reservations from House Speaker Thomas P. O'Neill Jr. (D-Mass.) that it would only embarrass Reagan when his budget went down to almost certain defeat. "At some point you have to cut bait and just do it. It wouldn't hurt a thing."

Jones contends that it may take a vote on Reagan's budget to break what he and many others regard as a stalemate on the issue in Congress. But some other Democrats say it is a ploy that could backfire, especially if the Democrats don't have a winnable plan of their own. House Republicans didn't seem very enthusiastic either.

Meanwhile, the Senate Appropriations Committee gave Reagan's budget another jolt in approving a range of spending estimates for next year that exceeded Reagan's targets for non-defense spending by anywhere from $200 million to $17.7 billion.

The lower figure assumed major cuts in benefit entitlement programs that would have to be made by other committees. Even the higher figure "does not fully include all possible contingencies and requirements which may arise" next year, according to a committee report.