Greece on Tuesday said it was suspending flights to and from Qatar until June 15 after multiple coronavirus cases on a flight from Doha to Athens.

The Greek civil protection authority said 12 out of 91 people on a Qatar Airways flight that arrived on Monday had tested positive for COVID-19.

"Following these epidemiological facts, flights from and to Qatar are suspended until June 15," the agency said in a statement.

Among those that tested positive on Monday's flight were nine Pakistani nationals who are legal residents in Greece, two Greeks from Australia and a member of a Greek-Japanese family, the statement added.

They will be quarantined at a hotel for two weeks, it said.

The official tourism season in Greece starts on June 15, when hotels operating during the season reopen and some regular flights from abroad resume.

But planes will only be flying into Athens and Thessaloniki in the north – and only from those parts of Europe and the world that escaped the worst of the pandemic.

Other Greek airports are due to open on July 1.

Tourism is a crucial part of the Greek economy, accounting for 20% of the country's economic output, and the lockdown imposed in March hit the country hard.

The country of 11 million has registered fewer than 180 deaths from COVID-19, and the government has pledged to protect this close-to-clean bill of health with additional resources sent to popular destinations such as islands.

The Greek health ministry earlier Tuesday said it had begun voluntary antibody tests on staff in hospitals, health centers and other related facilities.

Athens in May said it had acquired 200,000 COVID-19 antibody tests from U.S. medical giant Abbott.