Auckland population headed for 2 million
Auckland's population is set to boom in the next 20 years to the point where nearly four out of every 10 New Zealanders will call the city home.
The region will be close to hitting two million people by 2031, and New Zealand's population is expected to reach 5.19 million people, according to Statistics New Zealand.
Auckland passed the 1.5 million population mark in June. There are more than 4.4 million people in New Zealand.
Last year, of every 100 people living in New Zealand, 34 of them were Aucklanders - by 2031, 38 in every 100 Kiwis will be Aucklanders.
The city will be joined by Queenstown Lakes, Selwyn and Waimakariri districts as the areas with the highest projected population growth rates over a 25-year period (2006-2031).
"Auckland has a slightly younger population than other regions, and younger populations tend to have more births and relatively fewer deaths," population statistics manager Andrea Blackburn said.
Christchurch, which lost an estimated 8900 people in the year ended June 2011, was projected to increase by an average of 1500 a year during 2012-16, and then and 2500 a year during 2017-31, the agency said.