The Soviet Union is expected to dramatically reduce economic aid to Cuba in January, and some legislators say a re-evaluation of political ties with the longtime ally may be next.

Cuban leader Fidel Castro has scoffed at President Mikhail S. Gorbachev's 5-year-old reform campaign, and some Soviet deputies say he continues to foment insurgencies around the world while ignoring the needs of his people."Some members of parliament . . . are fed up with the export of revolution. If they (Cubans) continue the so-called old course, we'll let them continue. But foreign aid won't be as it was before," said Nikolai V. Neyland, a member of the Supreme Soviet's Foreign Affairs Committee.

Officially, the Kremlin is sticking by Castro politically. But Castro's steadfast refusal of Soviet-type reforms may play a role when the national Supreme Soviet legislature considers a foreign aid bill.

Western experts estimate Soviet economic aid to Cuba at $5 billion a year, and military aid at about $1.5 billion. Soviet reformers say this is a luxury the country cannot afford when it can't feed its own people, and cuts are expected in trade talks beginning next month.

The foreign aid bill, proposed by Gorbachev, envisions a 75 percent cut in "gratuitous" foreign economic aid, apparently affecting all Soviet allies.

It would accompany a new policy, starting Jan. 1, requiring allies to pay convertible currency at world prices for most trade with the Soviet Union. That would end a practice of giving aid - in the form of favorable trade terms - to countries such as Cuba, Vietnam, North Korea and Ethiopia.

In other changes, the Soviets also are pushing for a thaw in U.S.-Cuban relations, a 31-year antagonism that nearly led to nuclear war over the 1962 Cuban missile crisis.

Gorbachev, preaching "new thinking" in foreign affairs, said during a visit to Cuba in 1989 that he rejected Castro's support for Communist revolutions in countries such as El Salvador, Angola and Nicaragua.

Still, the official reason given for the cutback in aid is economic.

"We have given up the state monopoly on foreign trade, given enterprises the right of access to the international market, given up ideological-ridden approaches which used to lead to waste of resources in relations with some countries," Gorbachev told the parliament last week.

The huge Russian republic, with 90 percent of the country's exportable energy, is seeking more say over some foreign policy questions and could lead the way in asking hard questions about ties with Cuba.

"We don't want to interfere in the internal affairs of Cuba. Cubans must decide for themselves," said Yevgeny Kozholkhin, chairman of the Russian legislature's committee on foreign relations.

"But as we come to any consideration (about aid), we should just consider what kind of regime we have before us."

At some point, "we must consider human rights," he said.

A hint of anti-Cuban sentiment in the national legislature emerged in October, when legislator Olzhas Suleimenov took the floor and criticized Cuba as a "totalitarian" state.

In November, an expose in the reformist daily Komsomolskaya Pravda reported that Castro has 32 houses, a personal security force of 9,700, and five children by his "present wife." That would shock many Cubans, who have been told only that Castro was divorced 35 years ago.