TEGUCIGALPA, HONDURAS -- As the Iran-contra affair drags on in Washington, the perception of a weakened Reagan administration is causing increasing nervousness in Honduras and other Central American countries, according to diplomats and Honduran sources.

The nervousness is leading to greater efforts by pro-U.S. countries in Central America to distance themselves from American policy in the region and from the Nicaraguan rebels known as counterrevolutionaries, or contras, the sources said. The anxiety, among both the Hondurans and the contras, stems from concerns that U.S. funding for the rebels will not be renewed, or will be severely restricted, leaving the contras unable to press their war inside Nicaragua and the Hondurans forced to host them.

"The Hondurans are reassessing their relations with the United States," a western diplomat said. "The military for their own reasons are taking a harder line vis-a-vis the contras."

Honduran military authorities "are starting to get jittery about what's going to happen on Jan. 20, 1989, or maybe even before," said a source close to the Honduran Army. "They don't want to be left holding the bag" in the next U.S. administration.

"For us, the important consideration is that the Iran-contra scandal weakens enormously the policy of the Reagan administration in Central America," said Manuel Acosta Bonilla, a leading Honduran lawyer and opposition politician. "This has generated a certain attitude of more independence by Costa Rica and Guatemala toward American policy." Costa Rican President Oscar Arias lately has been promoting a Central American peace plan that appears to be causing growing consternation in the Reagan administration. According to diplomatic sources, a recent meeting between U.S. special envoy Philip Habib and Arias in the Costa Rican capital went badly when Arias flatly rejected entreaties that the plan be amended to include a call for negotiations between the Sandinista government and Nicaraguan rebels.

A Central American summit to discuss the plan was postponed from June 25 until early August. Nicaragua has rejected the postponement, charging that it was instigated by the United States as part of an effort to change the peace plan, which calls for cease-fires between Central American governments and insurgents, an end to all foreign military aid to insurgencies, including the contras, and a timetable for "democratization" in Nicaragua.

The main U.S. objection to the plan is that it would cut off aid to the contras while leaving the Sandinistas in power and free of pressure, in Washington's view, to make their government more democratic or reach an agreement with the contras.

Earlier this year, there appeared to be a widespread perception in Central America that the Iran-contra affair was essentially a U.S. internal matter that was not affecting American policies or commitments here. The contras, buoyed by deliveries from the $100 million U.S. aid package approved last year, were insisting that the affair would not impede their efforts to reinfiltrate their forces inside Nicaragua from Honduran base camps.

Now, however, the erosion of the Reagan presidency from the effects of congressional hearings on the affair has turned contra leaders' thoughts to how to stretch the aid into early next year, rebel sources said. In addition, it has left Honduran authorities waiting for potentially more damaging revelations from Washington, and, apparently, taking some measures to soften the impact by distancing themselves from the contras.

In recent weeks developments here have underscored Honduran discomfort with the contras and concerns about U.S. policy. The developments in part appeared to reflect growing resistance in Honduras to allowing the contras to operate from Honduran territory. In mid-May, the opposition National Party sent a three-member delegation to Washington to discuss U.S. Central American policy with administration officials and congressmen. In one meeting with a State Department group headed by Assistant Secretary of State Elliott Abrams, the Hondurans asked if the United States had any "contingency plan" in case aid to the contras were cut off and the rebels had to retreat into Honduras, according to one Honduran participant, Gilberto Goldstein.

He said his group was told that there was "no need for a contingency plan" because U.S. aid would continue and the United States had "never abandoned" its friends. The lack of a contingency plan, or the unwillingness of U.S. officials to talk about one, left the Hondurans uneasy, Goldstein said.

"We believe it is completely the decision of the U.S. whether to support the contras or not," he said. "However, if the decision is not to give support, we feel there is a moral obligation on the part of the U.S. government to find a solution for the contras, and not in Honduras. We could not possibly host a frustrated, defeated, armed, angry group of rebels."

Last week, three members of a new contra umbrella organization, the Nicaraguan Resistance, arrived in Tegucigalpa for a meeting. In an apparent reaction against the publicity surrounding the meeting, Honduran authorities refused to allow it to go ahead, asked the three contra leaders to leave and let it be known that three others planning to arrive from Costa Rica should stay home, Honduran sources said.

On June 8, President Jose Azcona said at a news conference, "I believe there won't be meetings of the contra leaders in Honduras" in the future.

Last week, the Honduran military reacted strongly when three contras crash-landed a Beechcraft Baron twin-engine plane inside Honduras after a mission into Nicaragua.

The Sandinistas said their groundfire damaged the plane and that it limped back into Honduran territory before going down. They said, based on intelligence reports, that the plane had taken off from the Honduran airfield of Aguacate and that its crew was made up of the commander of the contra air force, former Nicaraguan National Guard colonel Juan Gomez, and two other contras.

The identities of those on board were later disputed. Apparently concerned about Honduran sensitivities, the contras claimed that the plane had crash-landed inside Nicaragua and that the crew had been rescued by contra guerrillas.

Honduran authorities flatly contradicted this, saying that their troops had found the downed aircraft a few miles inside Honduras' El Paraiso Department. On Wednesday the Hondurans deported the three slightly injured crewmen to Miami because, according to a government statement, they had "violated the government's policy of neutrality and nonintervention in the internal conflicts of other states."

The Honduran military and the U.S. Embassy denied that the incident signaled a tougher attitude toward the contras.

"Our policy has been consistent," said the Honduran Army spokesman, Col. Manuel Suarez Benavides. "If someone acts in a way that violates Honduran policy, we have to respond."

A diplomat said the expulsions "do not represent a hardening of the Honduran position toward the contras. It's a tense time right now, and things will probably clear up in the near future."

According to a military expert, Honduran officers are wondering what is going to happen to their country as a result of President Reagan's "weak position." Although a recent U.S. decision to go ahead with a sale to Honduras of 12 F5 fighter planes may allay officers' concerns about U.S. policy, the source said, "there is long-term apprehension on their part."

According to Honduran and foreign diplomatic sources, signs of a less accommodating attitude toward the contras and U.S. policy by the Honduran Army reflect an consolidation of power this year by a group of lieutenant colonels who are reputed to be more nationalistic and independent-minded than the Army's older U.S.-trained officers.

The military is also concerned, Honduran sources said, that further revelations from Washington about the Iran-contra affair may implicate individual officers who allegedly benefited from allowing the rebels to operate on Honduran territory. Such revelations could be used in a continuing power struggle within the armed forces, one Honduran analyst said.