The Pacific nation hopes to be able to bring in around 66 million Australian dollars (over 410 million kronor) through the sale of what is called a "climate-resilient citizenship".
Since the launch in February, only six passports have been issued so far, but according to official sources, the interest is great.
There has been a great demand but we did not have the opportunity to immediately start processing the requests, says Edward Clark, who is responsible for the passport campaign, to AFP.
The country hopes to be able to sell around 500 passports. Among the first buyers is an anonymous German family living in Dubai.
The Pacific nation of Nauru, with its 21 square kilometers, is one of the world's smallest countries and extremely vulnerable to rising sea levels. Researchers have found that the sea level is rising 1.5 times faster there than the global average.
A previous attempt by the country to sell passports, over 20 years ago, ended less successfully. It resulted in the authorities issuing passports to, among other things, members of the notorious terrorist group al-Qaida, who were later arrested in Asia.
Previously, Nauru's main source of income was the extraction of phosphate, which was used in the production of fertilizers. The deposits have now been depleted, but around 80 percent of the country is now uninhabitable as a result of previous mining.
