For several years, the Republic of Maldives has been leasing bits of its tropical island paradise to anybody with the cash. A group of West German nudist snapped up one deserted island, and another went to several European tourist agencies that offer unique vacations.

Yesterday, however, the leader of the archipelago republic made it clear that his government's rent-an-island policy does have certain limits.

President Ibrahim Nasir disclosed that the Soviet Union had tried to lease an abandoned British air base in the Maldives for $1 million-a-year, and Nasir said he had turned Moscow down.

In an interview with Reuter in Male, Capital of the Maldives. Nasir said the Russians wanted to lease the former Royal Air Force base on Gan Island, in the extreme south of the island chain. Gan is about 200 miles north of the U. S. base at Diego Garcia.

The reason for the Maldian rejection of the Soviet bid. Nasir said, was that his government did not want another superpower controlling an island in the Indian Ocean.

The Maldives, which became independent from Britain in 1965, had granted the Ganbase to London rent free until 1986. But the British decided in 1974 to reduce their military presence east of the Suez Canal, and 18 months ago, they abandoned the base leaving its 8,700-foot runway, radar and other electronic installations in full working order.

The Maldivian government beset by a chronic shortage of hard currency, put the island on the market, specifying that it should be used for commercial purpose.

American officials said yesterday that a Soviet military delegation visited the Maldives last June, and Russia's offer to lease Gan was made shortly thereafter. Nasir said Moscow's stated purpose for acquiring the base was to use it for maintenance of Soviet fishing vessels operating in the Indian Ocean.

The Maldive leaders, however, apparently had doubts about Soviet intentions. Their need for currency was apparently outweight by fears the venture could compromise their nation's nonaligned position.

American officials here said yesterday that the U. S. was gratified by Maldivian decision.

It appeared to be in keeping with the Maldive's general policy of attempting to attract foreign tourism and investment while isolating the Maldivian population from foreign influences, officials said.

The country is well suited for such approcah. It consists of a chain of 2,000 islands (of which only 215 are inhabited) strung out over a 500-mile stretch of the Indian Ocean.The total population stands at 130,000, and the islanders are predominantly descendants of Sout Indian and Sinhalese people mixed with descendants of Arab traders.

The Maldivians, who accepted Islam in the 12th century, have been trying to keep foreigners out of the populated island in order to preserve their culture and traditions. Non-populated islands, however, can be leased by foreigners.

American officials familiar with the Maldives say the islands offer enormous tourist potential becauseof their tropical climate and lush vegetation.