They actually wanted to celebrate the turn of the year with a cruise from New Zealand to Australia - but then the dream trip turned into a nightmare: Because of an infestation with microorganisms on the hull of their ship, the approximately 800 passengers on the "Viking Orion" were not allowed to go ashore for a week.

The Australian news agency AAP reported that "maritime growth" had formed on the outer wall of the luxury liner, so-called biofouling.

Such colonization of organisms can lead to the introduction and spread of non-native species.

Australia has very strict rules on biosecurity risks, among other things, to protect its unique flora and fauna.

After the ship set sail in the New Zealand capital of Wellington on Boxing Day, four ports refused to dock: Christchurch and Dunedin on the South Island, as well as Hobart in Tasmania, Australia, and Adelaide in South Australia.

Before the ship was allowed to set course for Melbourne, it first had to be cleaned by professional divers outside Australian waters - about 22 kilometers off the coast of the city of Victor Harbor.

"The ship needs to be hull cleaned to remove biofouling and prevent potentially harmful marine organisms from being introduced from the ship," AAP quoted the Ministry of Fisheries as saying.

According to the website, the Viking Orion is now on its way to Melbourne.

Viking Cruises said the ship is expected to continue sailing on its scheduled itinerary on Tuesday, although it had to skip several scheduled shore stops to carry out the necessary cleanup.

The captain apologized to the guests.

They are to be compensated later for the failed shore leave.