The Sao Tome and Principe government is demanding its share of the income from the more than 300,000 porn websites which use its internet suffix - .st.
Sao Tome residents hope the discovery of oil will transform their lives
"Sao Tome doesn't receive a thing," its infrastructure minister told London's Financial Times newspaper.
A survey in June found three-quarters of the porn sites using Africa-based internet addresses were in the tiny, oil-rich islands of Sao Tome.
Sao Tome has 27 porn pages for each internet user, the survey found.
Infrastructure Minister Deolindo Costa de Boa Esperanca said that he was shocked to find that in 1999, new managers were appointed for Sao Tome's domain name.
They sell the .st suffix to whoever they want and the government can do nothing, as the use of domain names is run by a United States-based non-profit organisation, the Internet Corporation for Assigned Names and Numbers (ICANN).
WORLD'S TOP PORN HOSTS
Germany: 10m pages; 295/1,000 internet user
UK: 8.5m pages; 339/1,000 internet user
Tonga: 849,000 pages; 287,473/1,000 internet user
Sao Tome: 307,000 pages; 27,365/1,000 user
Source: Secure Computing
Correspondents say the people behind porn sites prefer to use web addresses of countries where there is little internet regulation.
Mr de Boa Esperanca said Sao Tome has had an "image problem" since the California-based Secure Computing survey was published.
Sao Tome, with a population of 164,000 hosts 307,000 porn sites, out of 389,000 for the whole of Africa, the survey said.
While Sao Tome hosted the most porn sites in Africa, Germany and the UK came top worldwide, after the United States, which was excluded from the survey.
But in terms of porn pages per user, Tonga came above Sao Tome, with 287.