The French Polynesian government has declared a dengue type 2 epidemic on the island of Tahiti.
French Polynesia had been spared a dengue type 2 epidemic for about two decades which means that the public has low immunity to the disease.
The mosquito-borne illness has spread since the arrival in February of a traveller from New Caledonia infected with the virus.
Despite efforts to eliminate mosquito breeding sites, the new strain has spread.
The government says those most at risk of infection are people below the age of 20 and those who arrived in Tahiti after 2000.
Dengue type 1 is affecting more than a dozen people across several French Polynesian archipelagos, including the Marquesas.
New Caledonia declared a dengue type 2 epidemic in December.