DES MOINES, Iowa - Iowa Governor Kim Reynolds is now part of a national focus on vaccine passports.
Reynolds has joined a growing number of Republican governors and the Democratic Biden administration in opposition to the concept.
But some businesses and schools see the passports as a way to revive activity by confirming people are vaccinated against COVID-19.
The divide has led to wide ranging legal and ethical questions about the use of passports.
Republican governors in Florida and Texas have taken executive action to ban vaccine passports, and the Biden administration has said it won't support their usage on a federal level.
Reynolds said vaccination should remain a personal choice at her Wednesday news conference. She said the passports would create a "two-tiered society" and raise privacy issues.
"I strongly oppose vaccine passports, and I believe that we must take a stand as a state against them, which I intend to do either through legislation or executive action," said Reynolds.
The governor also said she is looking into how wide a ban on the passports could be, and whether it could be imposed on private businesses.
Meanwhile, some cruise lines plan to require vaccination proof from their travelers. And several universities are requiring vaccinations in order for students to return to campus in the fall.
Some legal experts have said businesses and schools can legally require proof of vaccinations, and that governments can also ban the use of vaccine passports.