Auckland, Queenstown and Canterbury's Selwyn District are set to boom, with latest population projections showing they will lead an increase over the next 20 years.
Figures from Statistics New Zealand released on Monday show that the proportion of New Zealanders living in Auckland will have grown to 38% in 2031, from 34% in 2011, as the city's population reaches two million.
Statistics New Zealand projects a total population of 5.2 million, with the fastest growing areas such as Auckland and Queenstown leading the charge.
Growth will be stronger in the North Island than the South Island, with nearly 75% of the North's growth being in Auckland, fuelled by immigration and a higher birth rate.
Of New Zealand's 67 territorial authorities, 44 are projected to grow. But areas such as Invercargill, Waikato and Westland may lose people.
Christchurch is expected to turn around its declining population as people start to return to the South Island city following the recent devastating earthquakes.
This will peak in 2017, when more than 2500 people move into the city each between then and 2031.
The director of Auckland University's local government centre believes the city will become less European and more ethnically diverse as its popularity increases.
Peter McKinlay says in 2006, 66% of Auckland's population was European but by 2021 this is expected to decrease to 53%.
Growing modern cities are attractive to migrants because they are dynamic and generally offer more opportunities, he says.