Salvadoran Defense Minister Jose Guillermo Garcia indicated yesterday that he believes a naval blockade of neighboring Nicaragua to prevent arms from reaching leftist guerrillas in El Salvador would neutralize the insurgents seeking to overthrow the U.S.-backed government in his country.

Col. Garcia indicated that El Salvador's civilian-military junta has not asked for such a move, intimating instead that such a decision is up to the United States.

There have been widely circulated reports in the press that a blockade is one of a number of options now being studied by the administration, although administration officials said yesterday that no decisions have been made.

At his news conference yesterday, however, President Reagan sought to dispel reports of more vigorous U.S. action. He said that while the United States would continue giving economic aid to El Salvador, he did not believe the situation "requires in any way, nor have we considered, aid of the kind of actual military intervention on our part."

Garcia stressed, during a breakfast interview with Washington Post reporters and editors, that his troops maintain total control of the country. He said that he and Secretary of State Alexander M. Haig Jr. "see the situation from the same point of view," but added that they have differences over "the form of the response." He said: "The United States has its views. We have ours."

Haig has said he believes the military situation within El Salvador is at a stalemate. He reportedly has asked the Pentagon to explore measures such as blockading Nicaragua and conducting show-of-force maneuvers near Cuba to deter these two countries from aiding the Salvadoran guerrillas.

While Haig has said he will not discuss specifics, he also has refused to rule out U.S. resort to outside actions designed to affect the fighting within El Salvador. The threatening tone of his statements has triggered shrill charges from Cuba and the Soviet Union that a U.S. invasion of Cuba is imminent.

Defense Secretary Caspar W. Weinberger and the Joint Chiefs of Staff, however, are understood to be resisting the idea of a blockade or other military measures on the ground that it might provoke a Soviet response in other areas of the world.

There also is concern in the Pentagon that the American public, fearful of El Salvador becoming a new Vietnam-type situation, would oppose strongly any escalation of the U.S. role in the Salvadoran conflict.

Yesterday morning, Garcia said the junta, headed by civilian President Jose Napoleon Duarte, would continue to pursue its campaign against the guerrillas "inside our own territory."

Garcia then was asked whether his military problems would be solved by a blockade that would prevent Cuba and other possible suppliers from shipping arms into Nicaragua so they can be smuggled to the guerrillas in El Salvador. He answered: "Yes."

There was no immediate indication of how Garcia's views about the effectiveness of a blockade will influence the debate going on within the administration about whether the United States should try to deal with El Salvador's two-year-old civil war by taking actions outside that Central American country.

Senior U.S. officials said yesterday that while various options are under study, no decisions have been made about using any of them. In several recent statements, Haig has made clear his concern that continued military stalemate, coupled with a deteriorating economic situation, could lead to eventual victory for the guerrillas, whom the administration regards as communist-controlled.

Garcia cited U.S. public concern over involvement in his country's civil war as a reason why the Salvadoran government will not ask the United States to send combat troops or sizable numbers of new military advisers there. He said: "We never want to compromise ourselves with other countries or make into a reality the speculation that we know is going on in the United States about a Vietnam syndrome."

The defense minister, who is the most influential figure in the Salvadoran armed forces and, many believe, in the government itself, reiterated that he does want more U.S. communications and transportation equipment to combat the guerrillas.

"As Winston Churchill said, 'Send us the means so we can do our own work.' We never will ask for men to resolve our problems," Garcia said.

Garcia also elaborated on his statement, made originally at a Monday news conference, that it is wrong to regard the civil war as stalemated. He said the guerrillas are conducting a widespread terrorism campaign that he conceded "is very difficult to combat."

He insisted, however, that the current guerrilla activity is being conducted out of desperation because of the failure of the insurgents to win significant support from the Salvadoran people or to gain power through direct military action.