Earlier this week, Hurtigruten admitted serious failings in the way it dealt with the outbreak onboard MS Roald Amundsen spanning two back-to-back sailings over 14-24 July and 24-31 July.

The NIPH department director Line Vold confirmed on Wednesday (5 August) a further seven new cases have been confirmed among passengers, and two more among crew, bringing the total number to 53 – 16 passengers and 37 crew.

Four crew have been hospitalised after contracting Covid-19, two of whom have since since been discharged.

Meawnhile, passengers from seven counties in Norway have now been confirmed to have the infection.

"The passengers on the two voyages must be quarantined and followed up by the local health services where they live," said the NIPH in a statement, confirming the quarantine period should be 10 days, which has now expired following the first voyage.

"It is important all municipalities [in Norway] now receiving inquiries from passengers from MS Roald Amundsen and the voyage from 24-31 July prioritise testing, so we can get an overview at the national level of the consequences of the outbreak, and thus prevent further spread," said Vold, adding passengers not displaying symptoms should also be tested.

Hurtigruten resumed sailing in June, starting with coastal operations off Norway, and embarked on its first expedition voyages last month. It has since suspended all upcoming expedition voyages onboard MS Roald Amundsen, MS Fridtjof Nansen and MS Spitsbergen until further notice.

Chief executive Daniel Skjeldam said the line’s initial investigation into the outbreak "uncovered several deviations from procedures", adding he recognised the incident had caused "a demanding and serious situation".

In a statement, Hurtigruten confirmed 37 crew had tested positive, with four having been taken to the University Hospital of North Norway. Two have since been discharged and are now in quarantine.

"According to the Norwegian Institute of Public Health, 16 guests on voyages with MS Roald Amundsen on 17 and 24 July have tested positive," the line added.

"The safety and wellbeing of our guests and colleagues is Hurtigruten’s number one priority. We are working closely with the Norwegian national and local health authorities for follow-up, further testing, and infection tracking."