Malta reversed plans to introduce a ban on unvaccinated travellers just hours before it was due to come into effect Wednesday, with those without coronavirus jabs able now to quarantine.

"Persons who arrive to Malta from any of the countries listed... without being in possession of a vaccination certificate shall be required to submit themselves to a period of quarantine," the government said in a legal note issued late Tuesday.

The length of the quarantine period was not immediately clear, although Malta had already imposed a requirement for those arriving from certain "red" countries to spend 14 days in self-isolation.

The Mediterranean island nation last week said it would become the first European country to impose a ban on unvaccinated travellers after a spike in Covid-19 cases.

But that announcement drew criticism from the European Commission, as it risked undermining an EU-wide travel certificate that shows whether someone is vaccinated, has recovered from coronavirus or has recently tested negative.

Health minister Chris Fearne had appeared to shut the door completely on US tourists and others, saying last Friday that only a Maltese, British or European vaccination certificate would be valid for entry.

However many more countries are included in the new legal notice, which comes into effect on Wednesday, including most of the United States, Japan and others.

Unvaccinated Malta residents who found themselves outside the country when the rules changed can show a negative PCR test, as long as the country involved is on the approved list.