Congressional Republicans moved yesterday to force a prompt vote -- possibly as early as today -- on Ronald Reagan's new tax-cut proposal, and dared Democrats to oppose it in the absence of a Carter administration alternative.

A group of GOP senators led by Bob Dole of Kansas announced plans to try to tack Reagan's $22.3 billion tax-cut prescription onto a pending debt-ceiling bill, with a vote possible this afternoon if the Democratic leadership agrees to the scheduling.

Reagan's proposal is for a 10 percent across-the-board tax cut for individuals, effective next Jan. 1, combined with faster depreciation writeoffs for business investment. It sent jitters through the Democratic cloakrooms.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) publicly dismissed the GOP presidential candidate's plan as inconsequential, telling reporters that Republicans "have small minds" when they consider national issues.

However, Democratic sources conceded that the Reagan initiative would heighten pressure for a Carter administration tax-cut proposal, and said House leaders most likely would raise the issue with the president next week.

"They'll be starting to press the issue with the administration," one key Democratic insider said. "This is very awkward of us, obviously. It's a clear game of one upsmanship."

Reagan announced his proposal at a press conference in Los Angeles during which he flayed Carter's economic record as "empty rhetoric" that has thrown the nation into a recession.

Alluding to the administration's current indecision on a tax cut, Reagan charged that the White House "continues to fiddle while the American economy chokes on what could well become the worst recession in half a century."

Dole told reporters at a press conference yesterday that approval of the Reagan plan now would take the tax-cut issue "out of election-year politics. We're willing to cooperate," he said. "We hope the Democrats would want to join us."

Dole said if the plan is defeated on the debt-limit vote, the GOP senators will try again on every major bill to come before the Senate. Tighter House rules prevent similar efforts in that chamber.

Republican sources acknowledged privately that Dole's invitation was primarily a political ploy and said it was unlikely that many Democrats would defect this far in advance of the November election.

Both the Carter administration and key Democratic congressional leaders have been reluctant to move quickly on a tax-cut plan, primarily for fear of upsetting their earlier anti-inflation budget-balancing effort, which has wide voter support.

President Carter's top economic advisers have begun considering a $15 billion to $25 billion tax reduction, also for 1981, but the White House has not decided on either the details of the plan or when to announce it.

The administration had been considering proposing the new package in its next formal revision of the budget, now scheduled for mid-July. Reagan's move has thrown those plans into confusion.

The Californian's announcement yesterday was designed to accomplish two things:

Pre-empt Carter on the tax-cut issue by beating him to the punch with a simple, easily understood plan having a definite January 1981 date -- in effect challenging the administration to come up with a rival.

Free Reagan from embarrassing Democratic charges that his previous tax cut proposal was "inflationary" and "irresponsible."

Reagan earlier had endorsed a 30 percent tax cut over three years -- a reduction so ambitious that it was challenged even by some Republicans. His new proposal is more in line with traditional GOP and Democratic tax-cut plans, including the one Carter is considering.

In announcing his tax-cut proposal, Reagan stopped short of proposing specific companion cuts in spending but called generally for a gradual reduction of outlays in relation to the size of the economy.

Reagan advisers said privately that the former governor would support a recommendation by his economists to pare federal spending to 19.5 percent of the gross national product -- a cut of $120 billion over four years.

The floor strategy announced by congressional Republicans later yesterday was endorsed by a full array of senators and congressmen, including the two who drafted Reagan's previous plan, Sen. William V. Roth (Del.) and Rep. Jack Kemp (N.Y.).

Roth called the one-year Reagan plan "a down payment" on his own broader three-year plan. Kemp charged that Carter "not only seems to have forgotten the hostages in Iran, but the American working man and woman."

Besides the Reagan tax-cut plan, Republican senators also hope to tack onto the debt-ceiling bill a proposal by Sen. William Armstrong (Colo.) to "index" federal tax rates each year to offset the impact of inflation.

The two were separated primarily for tactical reasons. Reagan has endorsed both the tax cut and indexing, but GOP leaders believe the latter may not muster as many votes in the Senate.

It was not immediately clear how the Reagan proposal yesterday would influence the administration's decision on a tax cut.Some Carter advisers were said to be urging the president to delay any more, portraying such caution as "prudent."

Carter earlier had hoped to put off any move toward a tax cut as long as possible, in hopes of painting Reagan as "irresponsible" for proposing his earlier 30 percent tax reduction.

Reagan's announcement yesterday put the Democrats in disarray. Rep. Richard Gephardt (D-Mo.), a member of the House Ways and Means Committee, predicted the GOP move would "quicken the pace" of the tax-cut drive. CAPTION: Picture, Republicans' $22.3 billion tax cut prescription is outlined by Sen. Dole, Reps. Kemp and Conable, and Sens. Roth, Percy, Wallop, Javits and Boschwitz. By James K. W. Atherton -- The Washington Post