Senate Republicans, whose disarray produced a deadlock in the Budget Committee, are regrouping amid hopes they will set aside differences long enough to pass a 1984 budget resolution this week.
Sen. Pete V. Domenici, chairman of the committee, proclaimed Monday morning that he was ''very optimistic'' that the GOP would rally around a budget compromise that he has been trying to sell since late last week. Just 11 days ago the New Mexico Republican voted for another, essentially Democratic proposal , in order to move the deliberations out of his deadlocked committee and on to the full Senate.
The plan that left Senator Domenici's committee would be a direct hit at the White House. It would raise taxes, cut defense growth, and spend more than the President asked for domestic programs. But Domenici has promised to produce a much different final product on the Senate floor, and he appears to be making some progress in closed-door GOP meetings. The compromise plan now evolving promises to be much closer to the Reagan administration's wishes.
Chief elements in the compromise include:
* An increase in defense spending of 7.5 percent for 1984. Although not as high as the original Reagan request for 10 percent, the Domenici compromise would be higher than the 5 percent after-inflation growth offered in the Senate Budget Committee. The 7.5 percent figure would give the Senate some ''bargaining room'' when it goes to conference with the House, which has already voted a roughly 3 percent raise for defense.
* Domestic spending that would total about $11 billion more than in the Reagan budget. That increase could come down, however, as the Senate completes action on its budget resolution. Even some moderate GOP senators, inclined to favor increased domestic spending, have indicated that they would settle for $7 billion in domestic add-ons, and the Senate leadership indicates it won't block efforts to make savings in this area.
* Taxes remain the biggest sticking point in the negotiations. Domenici is seeking virtually no tax increases for 1984 and 1985, with a possible increase of $51 billion for 1986, as proposed by the President. Hard-line GOP tax opponents caused a deadlock in the Senate Budget Committee by refusing to go along even with the President's hint of a future tax hike, and could still be a roadblock to Republican unity on the budget vote.
''I'm opposed to any new taxes,'' said Sen. Gordon J. Humphrey of New Hampshire after a Republican caucus Monday.
But Sen. William L. Armstong of Colorado, seen by some as the most doctrinaire opponent of higher taxes, offered some hope he would go along in the end. ''I do expect to support the compromise when it's put together,'' he said.
The moderate Senate budget chairman has gone some distance to bring in the anti-tax faction. He proposes that only the 1984 and 1985 tax figures be mandatory. In other words, the big increase for 1986 would be only a projection, designed to show that the gaping federal deficit will be closed somewhat in the last half of the '80s. Under the Domenici plan, the budget would include no enforcement provisions for the '86 tax numbers.
Still another concern rumbling through the Senate is over the towering budget deficits, expected to approach $200 billion this year and going down only slightly during the next two years. No budget now being seriously considered would bring the red ink level down even to $100 billion, and the Reagan budget deficit is estimated at $185 billion for 1984.
''It's a great misfortune that that is the case,'' said majority leader Howard H. Baker Jr. (R) of Tennessee of the failure to curb deficits. But ''that's the best we can do.''