President Reagan yesterday accused unnamed opponents of his deficit-reduction budget compromise of endangering the economy in order to force a tax increase.

Reagan's attack came as Senate Republican leaders indicated that they may have to restore some domestic spending in order to win enough GOP support for passage in the Republican-controlled Senate, where the plan apparently is in trouble.

Speaking to a rally of business leaders and others who back the plan to cut spending by nearly $300 billion over the next three years, Reagan said of those who oppose it:

"They're the ones who are secretly hoping to raise taxes. Their last hope is to sabotage budget reform, so endangering the economy that Congress will be panicked into taking desperate measures which they hope will be a tax increase."

The plan, negotiated earlier this month between the White House and the Senate GOP, would more than halve deficits to $100 billion within three years, largely through major new domestic-spending reductions.

No tax increases are included, and Reagan yesterday called it a "taxpayer protection plan."

Indications of possible package revisions came from Senate Republican Conference Chairman John H. Chafee (R-R.I.) and Budget Committee Chairman Pete V. Domenici (R-N.M.) as consultations continued on support for the plan.

"As a result of these meetings, I expect there may be some corrections . . . . ," said Chafee, mentioning restoration of funds for student loans and Medicaid as examples.

"We don't have any [proposed changes] in mind . . . but that doesn't mean we won't listen to them," Domenici said.

However, in a meeting later with Senate Majority Leader Robert J. Dole (R-Kan.), farm-state senators urged modification of large cuts proposed for farm programs but received little encouragement, according to several participants.

"Lots of urging" for changes came from farm state senators, Sen. Charles E. Grassley (R-Iowa) said. Asked if it appeared likely that changes would be made, he said, "I doubt it."

Farm state senators, a dozen of whom attended the session, could be critical to acceptance of the plan, especially if Democrats remain unified in opposition. Minority Leader Robert C. Byrd (D-W.Va.) said after a Democratic caucus that Democrats "certainly" will have specific amendments and may support one or more alternatives to the plan.

At a closed-door luncheon with Senate Republicans, Office of Management and Budget Director David A. Stockman vigorously defended the plan's proposal to halve Social Security cost-of-living increases over the next three years, but many senators remained skeptical.

"It raised at least as many questions as it answered," Sen. Arlen Specter (R-Pa.) said.

Some senators also expressed concern that the plan includes a 3 percent defense-spending increase after accounting for inflation while proposing termination or drastic cuts in many domestic programs.

"If they had a figure other than 3 percent [for defense], they might get people to vote with them on Amtrak [subsidies] and other things," Sen. David F. Durenberger (R-Minn.) said. Amtrak rail passenger service would be eliminated.

House Republicans held the plan at arm's length after a Stockman briefing. "We've got a lot of missionary work to do," Minority Leader Robert H. Michel (R-Ill.) said.

"We're not [either] endorsing it or not endorsing it," said Minority Whip Trent Lott (R-Miss.), who said he opposes the Social Security cut.