Cuban-United States relations could be moving toward a more temperate phase if unconfirmed reports of a meeting between Secretary of State Alexander M. Haig Jr. and Cuba's Carlos Rafael Rodriguez prove true.
The reports of a Haig-Rodriguez session 10 days ago in Mexico City indicate that Havana and Washington are eager to lessen the escalating friction between them.
Secretary Haig, however, continues to make the US contention that Cuba, with an assist from the Soviet Union, ''has embarked on a systematic campaign of increasing interference against its neighbors.'' He emphasized the point during a meeting of the Organization of American States last week on the Caribbean island of St. Lucia.
A US spokesman at the Miami Conference on the Caribbean said last week that Washington has let Cuba know ''that we know what it is doing'' in the Caribbean.
But the US is willing to discuss the whole issue with the Cubans. State Department spokesmen make this clear.
The significance of a Haig-Rodriguez meeting, if indeed it took place, should not be minimized.
Next to Cuban President Fidel Castro, Dr. Rodriguez is probably the most important member of the Cuban government. A longtime Cuban Communist, he is Cuba's top diplomatic trouble-shooter and its leading economic specialist. During most of Castro's rule, he has been a minister without portfolio, but he now has the title of vice-president.
Castro turns frequently to Rodriguez when domestic and foreign problems surface. It would be natural for Dr. Rodriguez, who speaks good English and understands the US better than many Cubans, to be tapped for a meeting with Secretary Haig.
Rumors of the meeting, surfacing first in Mexico City newspapers late last week, are not denied by either the US or Cuba. State Department spokesmen refuse all comment on the issue.
The reports suggest that Mexican President Jose Lopez Portillo arranged the session in his effort to mediate Cuba-US differences.
Secretary Haig's Mexico City trip included a lengthy meeting with Mexican Foreign Minister Jorge Castaneda de la Rosa to discuss Nicaragua and the US view that the Central American nation is drifting toward totalitarianism. But Mr. Haig was in Mexico City long enough to have met with Dr. Rodriguez, who also was in Mexico.