Under new restrictions on Monday, citizens must have a "super green pass" to use modes of transport such as boats.
Italy's smaller islands will be left behind by the country's latest COVID-19 restrictions, an association has warned.
From Monday, Italy will only allow vaccinated citizens who have a "super green pass" to use public transport, such as planes and boats.
The pass will only work for Italians who have been fully vaccinated against the virus or have recently recovered from infection. A negative test will no longer be sufficient to use transport under next week's new rules.
But a number of officials have warned that some island residents will now be unable to travel to the Italian mainland and will find themselves in "forced exile".
"Sea and air transport ... represent the only possible link for some inhabitants," said Francesco Del Deo, president of the Association of Small Island Municipalities (ANCIM).
"Prohibiting access to these means of transport ... means condemning to forced exile the residents who, for various reasons, have not been vaccinated," he said.
In a letter to Italian Prime Minister Mario Draghi, ANCIM called for island residents to still use a negative test to travel to the mainland for "health, education or work reasons".
Most of Italy's 87 small islands -- which are represented by ANCIM -- have no permanent health facilities.
"It's a complicated situation," said Del Deo, who is also mayor of a municipality on the island of Ischia, off the coast of Naples.
"In a democracy, the rights of minorities must also be protected," he added, while also voicing his support for COVID-19 vaccines.
ANCIM has suggested that Italy could set up special areas on ferries for those islanders who travel with a negative test result.
"I personally am very much in favour of vaccines, but I believe that the super green pass requirement for ferries is an oversight by the government," said Dino Ambrosino, mayor of the island of Procida.
"Since there are no alternatives to reach the mainland, the islanders' right to mobility must be protected."
Italy has paid a heavy price for the pandemic with more than 137,000 deaths since early 2020.
But more than 85% of people aged over 12 are vaccinated, as well as more than 10% of children aged 5 to 11.
This article has been updated. ANCIM is Italy's National Association of Small Island Municipalities and represents 35 towns and over 200,000 total permanent residents.