Amsterdam: Italy has overtaken South Korea as the world's second-worst coronavirus-hit country, as Europe struggles to contain the worsening outbreak and questions grow over whether the true number of infections could be far higher than reported.

A day after approving a draconian plan to quarantine 16 million people in the country's north, the Italian government on Sunday announced the death toll had surged 57 per cent in just 24 hours to reach 366.

The total number of COVID-19 cases grew from 5883 to 7375 - meaning Italy has now surpassed South Korea as the country with the highest caseload outside China.

Iran has formally reported 6566 cases, however international health officials and the Australian government believes the outbreak there is much worse than the official figures.