The Reagan administration has recalled its ranking diplomat in Cuba for consultations amid speculation that an even stronger diplomatic move--possibly a complete break in relations--may be imminent.

Wayne S. Smith, head of the U.S. Interests Section here, told Cuban officials before his departure this afternoon that there is nothing exceptional about his sudden trip to Washington in light of the rapidly worsening relations between the two countries.

But the war of words between Washington and Havana has grown so hot that many diplomats and government officials here expect a major move by the Reagan administration to further underline its hostility toward the communist government of President Fidel Castro.

One possibility would be to replace Smith with a more hard-line supporter of Reagan administration policy toward Cuba. Smith is a career diplomat appointed to this post by President Carter and is regarded here as a moderate on Cuban-U.S. issues.

Another step would be to reduce the level of representation in the interests section, removing the "ambassador" from what fulfills the function of an embassy although it is officially a section of the Swiss Embassy. There has been no U.S. Embassy here since the United States broke full diplomatic relations with Cuba in 1961.

Many diplomats here are concerned, however, that Smith's visit could be the beginning of a complete break in the relations renewed at the "interests section" level in 1977.

The Cubans also are concerned about the possibility of more drastic measures, including a naval blockade, although they believe any such move would bring the United States into conflict with such U.S. allies as Japan, Canada and France as well as with the Soviet Bloc. Despite the longstanding U.S. embargo on trade with Cuba and U.S. efforts to discourage trade with Havana by its allies, more than 30 percent of this country's commerce is now with Western nations.

U.S. Secretary of State Alexander M. Haig Jr. has threatened to "go to the source" of arms shipments to leftist guerrillas in El Salvador and other Central American countries. Haig has pointed to Cuba as that source and said that no options will be excluded in deciding how to deal with it.

Through most of the winter and spring Castro attempted to maintain a posture of moderation and conciliation with the United States, and repeated both publicly and privately that Cuba is not now sending arms to Central American insurgents. But the Reagan administration continued to intensify its attacks on the Castro government.

In July, Castro suggested that the Central Intelligence Agency was responsible for an outbreak of dengue fever here. Washington denied the charge and pointed out that it had quickly authorized an exception to the trade embargo to permit the quick sale of pesticides to this country to fight disease-carrying mosquitoes.

Tuesday Castro returned to the harsh and inflammatory rhetoric of the 1960s when he repeated those charges and accused the Reagan administration of being "fascist" and "covered in blood" for its actions in El Salvador, its support of Israel and its increasingly warm relations with South Africa.

Within hours of the speech, the United States denied a visa to Ricardo Alarcon, a vice minister of foreign relations, and other Cuban officials who had been invited to a conference on U.S.-Cuban relations. This was the first time the United States has publicly refused a visa to the Cubans in recent years.

Sources close to Castro say that he is now convinced that the Reagan administration is searching for some pretext to invade or to increase pressure on the Cuban government in some other way.

"He is absolutely convinced that the Reagan administration is thinking of using even the bomb here," said one friend of Castro.

"During Reagan's campaign there was talk of a naval blockade or worse. Then you have Haig's recent remarks," said one U.S. official close to a congressional delegation visiting here.

"The Cubans have to take us at our word. In prudence they have to get ready. They are now convinced that we are determined to have at them. Castro's speech was not only very harsh, but it seems to be saying he's ready to go to the mat."