Norway will "temporarily tighten" rules for cruise ships, banning such vessels with more than 100 people from docking in Norwegian ports, after a recent Covid-19 outbreak on a cruise ship.
The ban would apply for at least 14 days, the government said on Monday.
"We must take these necessary measures to stop the spread of infection in Norway," said Bent Hoie, the health minister, at a press conference.
Ongoing cruises would be allowed to continue, but passengers and crew would not be allowed to leave the vessel until the final destination. No new cruises would be allowed during a 14-day period.
The government's announcement came after Norwegian cruise and shipping line Hurtigruten announced it had temporarily suspended all expedition sailings for its three cruise vessels after a Covid-19 outbreak among passengers and crew.
Iselin Nybo, minister of trade and industry, said the incident "shows that the coronavirus pandemic is not over."
She added that the ban would only apply for cruise vessels, but not passenger ferries in regular service.
Hoie said crew members on cruise ships operating in Norway would have to self-isolate for 10 days on land before they start to work on board.
41 infected on board
Hurtigruten earlier said 36 crew members and five guests on the MS Roald Amundsen tested positive for Covid-19 on arriving at the Norwegian port of Tromso on Friday.
"We have failed and made mistakes," Hurtigruten chief executive Daniel Skjeldam later told reporters.
The company had not had sufficient checks regarding self-isolation of foreign crew members, and failed to apply other rules.
Skjeldam said the company had commissioned an external review to study possible shortcomings.
The Hurtigruten decision affects three vessels, the MS Roald Amundsen, MS Fridtjof Nansen and MS Spitsbergen.
The company said it was working closely with the Norwegian Institute of Public Health.
More people at risk
Separately, Norwegian police said they were investigating whether there had been possible breaches of the infectious diseases act onboard the MS Roald Amundsen.
Some passengers were allowed to disembark before the ship announced it was dealing with an outbreak of coronavirus, triggering fears of a local outbreak in Tromso and other places.
More than 380 passengers are waiting for test results, public broadcaster NRK reported.
The institute at the weekend said the infections were linked to two cruises during July around Svalbard, an Arctic archipelago administered by Norway.
Hurtigruten also runs a ferry and shipping link between Bergen and Kirkenes and said it would continue to operate that line.
Norway had on Monday recorded 256 coronavirus-related deaths and about 9,200 infections.