New Zealand is made up of two main islands and a number of smaller islands, located near the centre of the water hemisphere. The main North and South Islands are separated by the Cook Strait, 22 kilometres (14 mi) wide at its narrowest point. Besides the North and South Islands, the five largest inhabited islands are Stewart Island, the Chatham Islands, Great Barrier Island (in the Hauraki Gulf), d'Urville Island (in the Marlborough Sounds) and Waiheke Island (about 22 km (14 mi) from central Auckland). The country's islands lie between latitudes 29oand 53oS, and longitudes 165oand 176oE.
New Zealand is long (over 1,600 kilometres (990 mi) along its north-north-east axis) and narrow (a maximum width of 400 kilometres (250 mi)),with approximately 15,134 km (9,404 mi) of coastline and a total land area of 268,021 square kilometres (103,483 sq mi) Because of its far-flung outlying islands and long coastline, the country has extensive marine resources. Its Exclusive Economic Zone, one of the largest in the world, covers more than 15 times its land area.
The South Island is the largest land mass of New Zealand, and is divided along its length by the Southern Alps. There are 18 peaks over 3,000 metres (9,800 ft), the highest of which is Aoraki/Mount Cook at 3,754 metres (12,316 ft). Fiordland's steep mountains and deep fiords record the extensive ice age glaciation of this south-western corner of the South Island. The North Island is less mountainous but is marked by volcanism.The highly active Taupo volcanic zone has formed a large volcanic plateau, punctuated by the North Island's highest mountain, Mount Ruapehu (2,797 metres (9,177 ft)). The plateau also hosts the country's largest lake, Lake Taupo, nestled in the caldera of one of the world's most active supervolcanoes.
Abel Tasman National Park in the South IslandThe country owes its varied topography, and perhaps even its emergence above the waves, to the dynamic boundary it straddles between the Pacific and Indo-Australian Plates. New Zealand is part of Zealandia, a microcontinent nearly half the size of Australia that gradually submerged after breaking away from the Gondwanan supercontinent. About 25 million years ago, a shift in plate tectonic movements began to contort and crumple the region. This is now most evident in the Southern Alps, formed by compression of the crust beside the Alpine Fault. Elsewhere the plate boundary involves the subduction of one plate under the other, producing the Puysegur Trench to the south, the Hikurangi Trench east of the North Island, and the Kermadec and Tonga Trenches further north.