Five passengers on board the cruise ship Pacific Dawn are in isolation because of swine flu as the vessel is on a stop-over in the French Polynesian capital, Papeete.
The health ministry says the five have been given Tamiflu as have an unspecified number of other people who were in close contact with the five.
The ship is carrying nearly 2,000 passengers and almost 900 crew.
It arrived from Samoa and will sail to Bora Bora before continuing its voyage to Hawaii and California.
Meanwhile, the government in New Caledonia says three swine flu cases have been detected among people who have not travelled abroad or been in contact with people believed to have the infection.
This comes as the total number of swine flu sufferers in the territory has risen to 46 after the first case was recorded three weeks ago.
Swine flu fears have prompted one small island mayor to ban cruise ships from Australia, which has thousands of swine flu cases.