Much of northern New Zealand, including Auckland, and parts of the South Island would be almost wiped out by rising sea levels if all the world's ice melted, according to new mapping by National Geographic magazine.
New Zealand would be among many countries to lose vast amounts of their landscape if the polar ice caps melted, the nature publication said.
A huge swathe of eastern Europe, the entire eastern seaboard of the United States, Bangladesh and a large chunk of China would disappear.
Australia would gain a new inland sea in its centre, and would lose much of the narrow strip of the east coast where four out of five Australians live, reaching as far round as Melbourne and Adelaide.
A similar, but smaller, body of water would expand across the upper North Island, across Waikato and the Auckland region.
Wellington would also be affected, along with the coast south of the Taranaki Bight. Christchurch and Dunedin would be under water, and Southland and Stewart Island would shrink as well.
The interactive maps published by the magazine show how the world would look if all the ice on land melted and drained into the sea, raising sea levels by 66m.
Niwa chief climate scientist Dr David Wratt said New Zealand would definitely be affected if the polar ice caps melted.
He said the latest Inter-Governmental Panel on Climate Change report's highest scenario led to a sea level rise projection of 52cm to 98cm by 2100, compared to the late 20th century.
He also said the IPCC report indicated global warming above a threshold of a few degrees could lead to the near-complete loss of the Greenland Ice Sheet over a millenium or more, causing a global sea level rise over that 1000-year period of about 7m.
New Zealand would "certainly" see a similar rise around its coastal and low lying areas if that scenario were to play out.
To view the National Geographic interactive map look here.