Florida Governor Ron DeSantis on Friday banned the use of "vaccine passports" in the southeastern US state, citing "individual freedom."
The Republican governor's executive order prohibits government offices from issuing any "standardized documentation" certifying that an individual has been immunized against Covid-19.
It also prohibits private companies in Florida from requiring any type of document from their customers certifying their vaccination, or immunity after they have recovered from the coronavirus.
The order by DeSantis, an ardent supporter of former president Donald Trump who is seen as a future potential presidential candidate, argues that "so-called Covid-19 vaccine passports reduce individual freedom and will harm patient privacy."
Earlier this week De Santis said such requirements imposed by the government on the private sector would be "unacceptable."
"You want to go to a movie theater. Should you have to show that? No. You want to go to a game? No. You want to go to a theme park? No. We're not supportive of that," he told a press conference on Monday.
The order came after The Washington Post reported that President Joe Biden's administration is developing its own guidelines for such passports as it seeks to lift pandemic restrictions in the United States.
Such a document is also being discussed internationally as part of a bid to revive travel and tourism.
China launched a system of passports in March, with citizens able to download the new certificates and use them to enter and leave the country. It is not mandatory and is only available to Chinese citizens.
The European Union is also set to propose rules for a vaccine digital "green pass" allowing people to move safely around the bloc or abroad.
In Florida, a state of 21 million people which is economically dependent on tourism, nearly six million have now received at least one vaccine dose.
As of Monday, vaccinations will be available to all the state's adult population.