Secretary of State George P. Shultz, continuing the administration's drive to persuade Congress to resume aid to Nicaraguan "freedom fighters," warned yesterday that "lasting peace in Central America will be impossible" unless the leftist Sandinista government is forced to change its behavior.

Shultz's remarks were a further sign that the administration plans to make a major test in Congress of its Nicaragua policy. Congress last year cut off funds for guerrillas, known as "contras."

Resuming aid to the rebels has been the leading element of President Reagan's campaign to make the Nicaraguan government cry "uncle," as he put it Thursday in his news conference.

However, initial congressional reaction to the president's attempt to swing public opinion behind the policy indicated that he was unlikely to overcome reservations and deep divisions that led to the funds' cutoff.

Such Democratic foes of covert aid as Sen. Claiborne Pell (D-R.I.), ranking minority member of the Foreign Relations Committee, and Sen. Patrick J. Leahy (D-Vt.) charged that Reagan wanted to combat Nicaraguan terrorism with U.S.-sponsored terrorism.

House Majority Leader James C. Wright (D-Tex.), generally supportive of Reagan's Central America policies, said, "I don't think we have any call to appoint ourselves as God's avenging angels and reform by force any government with whom we disagree."

On the Republican side, Sen. David F. Durenberger (R-Minn.), chairman of the Select Committee on Intelligence, said he believed that the comments by Reagan and Shultz were "a thinking-out-loud attempt to find a focal point" for dealing with Nicaragua.

"They are mistaken if they think the public is going to buy the idea of giving the CIA a big check to drop balloons in jungles or mines in harbors or hire people to slit throats in Nicaragua," he added.

Senate sources said that Durenberger and such other Republican leaders as Sen. Richard G. Lugar (R-Ind.) believed that the administration could not push a new covert action program through Congress. These leaders have been urging the White House to look for alternative, public means of aiding the contras, the sources said.

But, the sources noted, the leaders have been frustrated by apparent administration unwillingness to abandon the idea of covert action and seek other approaches. That seemed evident as Shultz echoed Reagan's militant tone of Thursday.

Shultz said the "vigorous armed opposition of the many Nicaraguans who seek freedom and democratic government" was the only force capable of diverting the Sandinistas from what he termed their "role of surrogate for the Soviet Union and Cuba" in Central America.

"Those who would cut off these freedom fighters from the rest of the democratic world are, in effect, consigning Nicaragua to the endless darkness of communist tyranny. And they are leading the United States down a path of greater danger," Shultz told the Commonwealth Club in San Francisco.

Shultz made his remarks within the framework of an argument that the United States has a moral responsibility to help bring about "a democratic revolution" throughout the world, whether in Poland, Afghanistan, Cambodia, Ethiopia, Angola or Nicaragua.

Referring to the late Soviet president Leonid I. Brezhnev, he rejected what he called the "infamous Brezhnev Doctrine, first proclaimed at the time of the Soviet invasion of Czechoslovakia in 1968."

"Its meaning is simple and chilling," Shultz said. "Once you're in the so-called 'socialist camp,' you're not allowed to leave. Thus the Soviets say to the rest of the world: 'What's mine is mine. What's yours is up for grabs.' "

The United States, he continued, cannot allow "this dangerous scenario to unfold" in Central America. Instead, he reiterated, Nicaragua must be forced to accept U.S. demands that it get rid of Soviet and Cuban advisers, reduce its armed forces, stop aiding leftist insurgents in such neighboring countries as El Salvador and allow Nicaraguan "opposition groups, armed and unarmed, to participate in the political processes of the country."

"Whether these goals are achieved through multilateral negotiations, through unilateral actions taken by the Sandinistas alone or in concert with their domestic opponents or through the collapse of the Sandinista regime is immaterial to us," Shultz said. "But without such a change of behavior, lasting peace in Central America will be impossible."

Shultz did not specify what form renewed U.S. aid for the contras should take, but his remarks left the clear impression that the administration would prefer a renewal of covert action. He said:

"There are efforts that are most effective when handled quietly. . . . In those few cases where national security requires that the details are better kept confidential, Congress and the president can work together to ensure that what is done remains consistent with basic American principles."

Shultz also repeated Reagan's contention that U.S. actions toward Nicaragua are consistent with the charters of the United Nations and the Organization of American States. U.S. officials said they were referring to sections of the charters that authorize individual or collective self-defense against aggression.

Nicaragua, in turn, has charged that the United States has waged aggression by supporting the contras. Many international-law experts here and abroad also contend that the administration has been selective in using the U.N. and OAS charters to justify its actions and, in some instances, has violated provisions of the charters.

The U.N. charter states that countries must report self-defense measures "immediately" to the Security Council. The OAS charter contains similar provisions.

The 1947 Inter-American Treaty of Reciprocal Assistance, which the administration has cited as the cornerstone of its security activities in Latin America, requires signatories that claim to be victims of aggression to inform the United Nations and to seek an immediate meeting of treaty members to act on the situation.

The United States has never notified either the Security Council or the OAS that it has engaged in covert action against Nicaragua.

However, the State Department said last night that "the situation in Central America has been brought to the attention of the Security Council on numerous occasions and the United States has clearly informed the council of our view that Nicaragua has committed armed attack against its neighbors and that we have been acting in collective self-defense with them."

Last year, when Nicaragua sought to bring a complaint about U.S. complicity in the mining of its harbors to the International Court of Justice, the United States refused to accept the court's jurisdiction. U.S. officials have admitted privately that they acted, in part, because the court's proceedings would have made public the U.S. covert actions and supported Nicaragua's claim.