President Reagan asserted today that the Nicaraguan rebels dealt a "resounding defeat" to Sandinista troops who invaded Honduras last weekend to attack rebel bases.

"Once again, the news for the forces of freedom was good," Reagan said in a radio address from his California ranch marking the Easter holiday. "The freedom fighters gave the invading communists a resounding defeat."

The president's claim was the most far-reaching yet by the administration about the conflict in Honduras, the size and scope of which has been questioned in Washington as Congress debates Reagan's proposal to provide $100 million to the counterrevolutionaries, also known as contras.

Reagan offered no substantiation for his claim that Nicaraguan troops were defeated. Administration officials have said that most of the Sandinistas have retreated into Nicaragua.

The administration has been embroiled in debate over its claim that 1,500 Sandinista soldiers in two battalions crossed into Honduras, which some sources said was an exaggerated estimate and which U.S. officials acknowledged was not precise. Reports from the scene indicated there was fighting along the border, but it might not have been as massive as the administration said.

In a political speech Thursday, Reagan said House rejection of the aid package had spurred the Sandinista offensive. After complaints from Democrats, a senior White House official acknowledged today that in private intelligence briefings congressional leaders had been given a different story -- that the Sandinistas carried out the incursion in an effort to wipe out the rebels before the United States could supply aid.

In today's Democratic response to the president, Rep. Lee H. Hamilton (Ind.), chairman of the House intelligence committee, said that providing funds for the contras will not accomplish Reagan's objectives of establishing democracy and fighting Soviet and Cuban influence in the region.

"Nicaragua is in every way more of a communist country now than it was four years ago when America began funding the contras," Hamilton said.

Reagan also used his radio address today to boast of U.S. military strength following last week's conflict with Libya over the Gulf of Sidra. Although officials have maintained that the U.S. 6th Fleet was only on a freedom-of-navigation maneuver in the gulf, Reagan heralded it as a blow against a sponsor of terrorism.

"This was a direct military confrontation provoked by Libya's dictator, Colonel [Muammar] Qaddafi, who usually prefers to arm, train and direct terrorists who gun down helpless civilians," he said, recalling the Rome and Vienna airport attacks of last December. The United States has accused Qaddafi of complicity in training the terrorists involved in those attacks.

"But last week, Colonel Qaddafi tried his luck with some people who could actually defend themselves -- United States armed forces . . . . "

Reagan, mixing talk of the religious holiday with accounts of the conflicts, explained the fighting on both fronts by saying, "You see, dictators, like those in Libya or in Nicaragua, know how unpopular they are with their people. They know how shaky their rule is. They can never really feel secure. And that's why they are afraid of free elections.

"It's also why they need a secret police and so much armed might to intimidate those they fear most -- their own people -- to prevent them from even entertaining the hope that democracy will someday come to their own country. And that's why so many dictators have a special fear and hatred for the United States.