The Cuban government has agreed to permit 480 dual citizens of the two countries to emigrate to the United States in a "very significant political and humanitarian gesture," Rep. Stephen J. Solarz (D-N.Y.) said yesterday.

Soarz had taken up the question of the dual citizens in a June meeting in Havana with Cuban President Fidel Castro.

The congressman said he was informed by Cuban diplomats here this week that approval has been given for these Cuban-Americans and their dependents, about 1,500 persons in all, to leave for the United States and that applications for emigration are being processed.

A State Department official said the first list of 298 Cuban-Americans has been received from the government in Havana, and is now being checked against records here. The official said the State Department is planning to bring the first of the emigres to Miami by charter jet within the next several weeks.

Solarz, in a news conference, called the decision to release the dual nationals "an indication of President Castro's desire, despite our differences over Africa, to normalize relations with the United States."

In return for this gasture, he proposed that President Carter consider taking several reciprocal steps:

Lifting the trade embargo to permit the shipment of U.S. medical supplies to Cuba.

Permitting the establishment of regularly scheduled commercial flights to and from Cuba.

Agreeing to a formal cultural exchange program.

Solarz said some of the dual nationals are of Cuban heritage who happened to be born in the United States, and others obtained American citizenship through their parents.