Vanuatu's national coronavirus taskforce has advised South Sea Shipping not to accept diverted cruise ships amid Covid-19 fears.
The taskforce's Russel Tamata issued the warning after the Carnival Splendor berthed in Port Vila on Friday despite not being scheduled.
The Vanuatu Daily Post reports the Carnival Splendor arrived in Port Vila the day after the Golden Princess had visited.
There were rumours on social media of suspected coronavirus cases on the Golden Princess.
Mr Tamata confirmed 14 passengers on board the boat had flu-like symptoms and were kept in isolation in their cabins.
"It was just part of our control measures after diagnosing passengers with flu symptoms to keep coronavirus out of our border," he said.
Need for Tahiti Covid-19 certificate queried
Meanwhile, French Polynesia's health minister has admitted there is no legal basis to demand that arriving passengers show a document proving they are free of the coronavirus.
Such a stipulation was announced to come into force last Monday but apparent confusion over its implementation prompted a deferral until this Monday.
However, the legality of the measure was called into question amid reports that passengers were allowed to board flights for Tahiti without producing such a certificate.
The minister Jacques Raynal said French citizens wanting to visit French Polynesia could not be refused entry because the territory was French despite its autonomy statute.
The public sector union has also raised the question of who will have to pay for the medical tests, which travellers say are difficult and costly to obtain.
The virus outbreak has meanwhile prompted Air Tahiti Nui to cut some flights to Japan.