New Zealand travellers are being warned about a surge of dengue fever in the Pacific and a strain that hasn't been seen in 20 years.
Eleven people have died in New Caledonia this year from the mosquito-borne disease and more than 4000 others have been affected.
More than 9000 Kiwis holiday in New Caledonia every year.
Dr Colin Tukuitonga of the Secretariat of the Pacific Community says there's normally one strain of dengue fever circulating, "but now we have two - both type one and type two - so it's a concern for us in the region without a doubt".
Type two hasn't been seen in the Pacific for 20 years. The symptoms of aching joints, headaches and fever are the same, but the absence of the strain until recently means many people haven't developed immunity to it.
As well as New Caledonia, the dengue strain is also in Vanuatu, Fiji, American Samoa and Palau.
Over the first six months of this year 71 New Zealanders were reported as contracting dengue overseas, mostly after travelling to the Pacific.
Travellers are being warned to take precautions when going to affected areas.