President Reagan called yesterday for increased U.S. aid to rebels fighting the Sandinista government of Nicaragua, saying the "freedom fighters" need "more effective help" to offset Soviet and Cuban arms shipments to the "thugs" running Nicaragua.

In his weekly radio address, Reagan did not specify how much additional aid he would seek from Congress. But White House officials said he was laying the groundwork for a request to increase assistance above the current $27 million in nonlethal supplies to the U.S.-backed contras, or counterrevolutionaries, seeking to overthrow the Sandinistas.

A White House official said the administration is "reviewing how we can do more" to support the rebels, possibly with military aid, in response to what he described as a growing Cuban military role in Nicaragua and continued suppression of civil liberties.

The official said the exact amount of additional aid had not been determined. Congress restored the nonlethal aid to the rebels in a compromise earlier this year after cutting off military assistance two years ago.

Reagan emphasized the Cuban involvement in Nicaragua yesterday in a speech that also directed a blast of criticism at the Sandinista regime, charging it with repressing citizens and the church. "Nicaragua today is an imprisoned nation. It is a nation condemned to unrelenting cruelty by a clique of very cruel men, by a dictator in designer glasses and his comrades drunk with power and all its brutal applications."

The designer glasses remark was a reference to the purchase of six pairs of eyeglass frames at $300 each at a designer optical store in Manhattan by Sandinista leader Daniel Ortega while he was in New York for the 40th anniversary of the United Nations in October. Ortega's wife reportedly purchased $3,500 worth of eyeglasses at the same time.

In a speech to the United Nations -- where he met Ortega at a reception -- Reagan proposed a regional peace process that would include Central America, but he made no mention of the idea yesterday.

"Their denial of rights, their trampling of human dignity, their wrecking of an economy with suffocating socialist controls all hurt and deeply offend us. But there is a cause for deeper concern -- the specter of Nicaragua transformed into an international aggressor nation, a base for subversion and terror."

Reagan said "some 3,000 Cuban military personnel now lead and advise the Nicaraguan forces down to the smallest combat units. The Cubans fly the Soviet assault helicopters that gun down Nicaraguan freedom fighters."

He also said that more than 7,000 Cubans, Soviets, East Germans, Bulgarians, Libyans and "other bloc and terror groups are turning Managua into a breeding ground for subversion." The president also claimed that a delegation of Nicaraguans is in Iran and said Managua had a role in the recent terrorist attack against Colombia's Supreme Court.

"If Nicaragua can get material support from communist states and terrorist regimes, and prop up a hated communist dictatorship," Reagan asked, "should not the forces fighting for liberation now numbering over 20,000 be entitled to more effective help in their struggle for freedom? Yes."

Reagan said he sent national security affairs adviser John M. Poindexter to Central America this week.