Land Information Minister Maurice Williamson has approved the original Maori names for the North and South Islands.
The names North and South will also be formalised, as they are not official names under New Zealand legislation.
The original names are Te Ika a Maui, meaning the fish of Maui, for the North Island, and Te Wai Pounamu, the waters of greenstone, for the South Island.
A Christchurch resident with an interest in New Zealand history was responsible for getting the original names considered after submitting a proposal to rename the South Island.
Mr Williamson says once adopted, the existing English names and the Maori names will be able to be used either individually or together.
Chairperson of the New Zealand Geographic Board Don Grant says the consultation process was thorough.
"We had three months of consultation and we got 2,600 responses to that which is a pretty large number.
For those who commented on the Maori names there was quite strong support for those names; about 65%."
Former chairperson of the Maori Language Commission Haami Piripi says it is a big step towards recognising the pre-European history and language of the indigenous people of New Zealand.
The two islands have never had official names until now, despite being charted in 1769 by Captain James Cook, who gave them Maori names similar to those confirmed on Thursday.