Out of approximately 300,000 or 310,000 square kilometres (117,000 or 118,000 sq mi) of land, over 270,000 km (1,400,000 sq mi) of continental shelf.
The oldest rocks in the region are found in New Zealand and are believed to be about 510 million years old.
The oldest Polynesian rocks outside of Zealandia are to be found in the Hawaiian Emperor Seamount Chain and are 80 million years old.
Polynesia is generally defined as the islands within the Polynesian Triangle, although there are some islands that are inhabited by Polynesian people situated outside the Polynesian Triangle.
Another term, the Polynesian Triangle, explicitly includes the Hawaiian Islands, as they form its northern vertex.
"Lapita Peoples", so-named after their pottery tradition, appeared in the Bismarck Archipelago of northwest Melanesia.
Geographically, the Polynesian Triangle is drawn by connecting the points of Hawaii, New Zealand and Easter Island.
The other main island groups located within the Polynesian Triangle are Samoa, Tonga, the Cook Islands, Tuvalu, Tokelau, Niue, Wallis and Futuna and French Polynesia.
Zealandia is believed to have mostly sunk 23 million years ago and recently resurfaced geologically due to a change in the movements of the Pacific Plate in relation to the Indo-Australian plate, which served to uplift the New Zealand portion.
At first, the Pacific plate was subducted under the Australian plate.
In pre-colonial times, Polynesian populations also existed in the Kermadec Islands, the Auckland Islands and Norfolk Island.