Aeroflot, the Soviet airline, said yesterday it is considering shifting its base of South American operations from Havana to Miami.

George V. Terentiev, vice president and commercial director for Aeroflot in New York, said fuel supply is becoming such a major concern in Cuba that the airline is looking for "some new place" to use as a refueling point for its flights to South American destinations.

"Maybe Miami will be the most convenient to use for that purpose," Terentiev said.

Under terms of a U.S.-Soviet agreement signed in May, the Soviet airline will be allowed to serve several U.S. cities in addition to its current routes into Washington and New York. They include Miami, Chicago, San Francisco and Anchorage. From Miami, Aeroflot may continue to no more than two South American destinations.

However, the Soviets now apparently are exploring an additional arrangement rare in aviation: an international hub to be used only for technical reasons, such as refueling, with no passenger boarding or deplaning.

A spokesman for the Miami airport said Aeroflot had discussed the arrangement but emphasized that no final decision had been made.

To obtain permission for technical stops, Aeroflot would have to jump through several regulatory hoops, first obtaining permission from the proper Soviet regulatory bodies, then from the State Department and the Transportation Department.

"There is nothing before us now, and we have had no discussions with them," said a Transportation Department official.

Aeroflot now flies from Havana to only one destination in South America: Lima, Peru. It also has service to Mexico and Nicaragua.

Aeroflot's fuel problems in Havana may be at least in part a result of Soviet policies. Cuba has announced fuel restrictions as a result of a shortfall of nearly 14 million barrels in Soviet fuel shipments, coupled with a surge in fuel prices nationwide.

Terentiev of Aeroflot said the airline also faces a hefty fuel price hike later in the year. He blamed the Persian Gulf crisis.

Terentiev said no final decision had been made on filing an application for permission to shift operations to Miami, but he emphasized the advantages of the move, including shorter route mileage from Moscow through Miami.

"I think Aeroflot will make the best economic decision," he said.