At least 40 passengers and crew from a luxury cruise liner have tested positive for Covid-19 and the authorities are still trying to trace a number of passengers from two recent Arctic voyages, according to Reuters.

Four crew members on the MS Roald Amundsen were hospitalised on Friday when the ship arrived at the port of Tromsoe, and later diagnosed with the respiratory illness. Tests showed another 32 of the 158 staff were also infected.

While the crew was quarantined on the ship, the 178 passengers who arrived on Friday were allowed to disembark before anyone had been diagnosed, triggering a complex operation to locate them in order to contain any potential spread.