Facing a rapid succession of U.S. diplomatic and military measures designed to pressure Nicaragua's Sandinista government, some of Washington's closest allies in Central America are expressing confusion about the direction of American policy in the area and a growing fear that crossed signals could lead to serious miscalculations and widening war.

Honduran Foreign Minister Edgardo Paz Barnica said in an interview today "the military attitude of the United States" toward neighboring Nicaragua is "a unilateral attitude" even though Honduras will participate in many of the military exercises announced during the last few days.

By sending aircraft carriers and escort ships to Central America's shores, Washington "could serve to provide pressure" for more fruitful negotiations between Nicaragua and its neighbors "or it could worsen tension," Paz Barnica said.

"That's why we have to have faith in the initiatives of Contadora," Paz Barnica concluded, referring to diplomatic efforts by Mexico, Venezuela, Colombia and Panama to promote talks among the Central American republics without any direct involvement by the United States.

Officials of three of the Contadora countries who met in Caracas, Venezuela, last week, joined the presidents of three other Latin American countries today in issuing a statement in Caracas calling for an end to foreign interference in Central America, one of the goals of the Contadora effort.

Cuban President Fidel Castro has also publicly expressed support for the Contadora initiative. The Mexican government newspaper El Nacional published a letter from Castro to the presidents of the Contadora countries saying, "We are sincere supporters of the fact that confrontation should be substituted by dialogue."

At least one of the Contadora presidents, Belisario Betancur of Colombia, will be visiting Central America this week in preparation for a meeting of the Contadora and Central American foreign ministers in Panama beginning Thursday.

The Nicaraguans, meanwhile, issued their most flexible negotiating agenda yet last Tuesday, even as some Sandinista officials warned that Washington and its Navy may be trying "to turn the Gulf of Fonseca into the Gulf of Tonkin" by forcing an incident or military confrontation that could prompt direct U.S. intervention.

Yet for all the movement toward the bargaining table there is still worry among many Central Americans that the most powerful player, the United States, is unsure of exactly what it wants and how to get it, what it will accept and what it will not.

"There is a sensation of confusion, of surprise," said a senior Honduran official reviewing the Reagan administration's recent moves toward peace and war.

"An American fleet, support for Contadora and at the same time for the contras and then saying Nicaragua's negotiating proposal is 'positive'; it seems no one voice is authoritative in policy," the official said. Central Americans call the U.S.-backed anti-Sandinista guerrillas contras, or counterrevolutionaries.

The clearest trend that has emerged from Washington appears to be toward confrontation with the revolutionary government in Managua.

While the Reagan administration's demands on the Sandinistas once focused mainly on ending their support for leftist insurgents in El Salvador, the current emphasis is on fundamentally changing the character of the revolutionary Nicaraguan government, which has taken a hard line in restricting political opposition.

A senior U.S. diplomat in the region suggested that other points of interest probably cannot be negotiated successfully with the Sandinistas until they change their approach to government.

"It is now considered that the only way they can be trusted to keep an agreement is to have the type of government which would force them to do so or make it a public issue," he said.

Asked why the lack of democracy in right-wing countries of the region does not provoke the same reaction from Washington, the diplomat said, "We have more influence over the others. You can trust them not to go against vital U.S. interests."

Despite their confusion about Washington's negotiating stance, Central American allies of the United States also say the Sandinistas must return to their original promises of conventional, pluralistic democracy.

Paz Barnica said today that "the problem is that there exists in Nicaragua a communist totalitarian government, and that is incompatible with our democratic system of life and of government."

Paz Barnica said that what Honduras seeks is "not precisely that the Nicaraguan government should fall but that it should democratize itself."

But when asked which of the negotiating points put forth in suggested agendas for this week's Contadora meeting is most important to his country, Paz Barnica said it was the question of stopping a regional arms race, not changing Nicaragua's form of government.

The role of the Reagan administration's recent appointees like special envoy Richard Stone and former secretary of state Henry A. Kissinger, who heads a bipartisan commission, have also befuddled both friends and opponents of U.S. policy in the region.

Diplomats are asking each other what the relationship between Kissinger and Stone will be and government officials in this and other countries have begun to talk of Stone as essentially a lame duck.

"Poor Stone seems to be left with his legs broken in the middle of the road," one Honduran politician said. "With Kissinger around who's going to want to talk to Stone about regional negotiations?"

Washington's proposed increase in financial support for anti-Sandinista rebels fighting to overthrow the Nicaraguan government is also an object of speculation and concern here.

As one military official put it, by keeping a "covert" wrap on the operation but pressing for ever bigger commitments, Washington could create a situation that could leave Honduras in an untenable position.

"If you have everything clandestine and the going gets tough then you can always fold your tents at night clandestinely and say, 'Look what those Hondurans got themselves into,' " the official said.

A question that has been asked repeatedly here is the extent to which the Reagan administration's policies are responding to political pressures in the United States. "If you sit down and scrutinize what's behind these signals from Washington then they seem little more than expressions of internal differences in the United States," one Honduran official said.