The Voyager of the Seas had travelled from the Italian city of Naples
There are conflicting reports over whether dozens of people on a cruise liner which docked in the south of France are suffering from swine flu.
French authorities say about 60 crew members on the 'Voyager of the Seas' have fallen victim to the illness.
But the luxury ship's operators, Royal Caribbean, say 62 crew and two guests suffering from cold- and flu-like symptoms tested negative for swine flu.
They are being kept in isolation, a statement from the company said.
The local authorities in the French department of Alpes-Maritime said those reported to have swine flu had been confined to their cabins while the ship was in the port of Villefranche-sur-Mer.
They said a further 70 crew members were suspected of having the virus, and isolated.
A French spokeswoman said the French authorities had been informed of the diagnosis by the Spanish health authorities.
She said those who are ill had been diagnosed on boarding the ship in Barcelona, and there was no information to indicate that the diagnosis from Spain was not correct.
It has also been to the Italian port of Naples as part of a tour of the Mediterranean.
The ship is carrying more than 5,000 passengers and crew.
It has now gone on to Marseille. The authorities there say neither passengers nor crew will be allowed to disembark until further tests have been carried out on their health.
"Based on the results, a decision will be made on whether or not passengers can disembark," a statement from the local prefecture, or local government, said.
In a statement, Royal Caribbean said the ill crew members had not affected the ship's itinerary or the level of service on board.
On Thursday, officials said a 14-year-old girl infected with H1N1 had become France's first fatality from the virus.
However, they cautioned that it did not appear that her death, at a hospital in the north-western city of Brest, had been directly linked to the virus.
Neighbouring Belgium also reported its first swine flu death on Thursday when a 34-year-old woman passed away after developing "a double viral pneumonia".
Deaths have now been recorded in five European nations - Belgium, France, Hungary, Spain and the UK, where 31 people have died.