The total population of the Pacific Islands is predicted to reach 10 million by the end of the month.
The Secretariat of the Pacific Community says the population of 22 countries and territories in the region will continue to rise and is expected to reach 15 million by 2035.
Its data shows the fastest-growing countries are Guam, Solomon Islands and Vanuatu, which are experiencing high birthrates.
In contrast, the populations of Niue and Tokelau are declining because of emigration to New Zealand.
The research also shows Polynesia and Micronesia have large populations of young people but lower numbers in the 30-40 age group.
This indicates that more people have migrated or are working overseas.