Auckland is likely to become the first city in New Zealand history to reach 2 million people in the early 2030s, based on new projections.
"Auckland will likely have the highest average annual growth of New Zealand's 16 regions over the next 30 years, from net migration and natural increase (more births than deaths) in relatively equal shares," said population estimates and projections manager Hamish Slack.
On Wednesday Statistics NZ unveiled its latest estimates for the city, which with 1.7 million people is already home to more than a third of Kiwis.
The low-growth scenario lands Auckland at 1.8 million by the early 2030s, and the medium-growth scenario at 1.9 million. But if recent trends continue, 2 could be calling Auckland home by then.
"The medium-growth projection suggests Auckland's population could expand by another 300,000 people by 2033 - an average of about 60 extra people every day, or 1900 a month."
By 2048, there could be more than 2.6 million, based on recent growth in the city.
Over the next 30 years, Auckland will account for about half of the entire country's population growth, Statistics NZ said.
Under low-growth scenarios, several regions could see their populations decline in that time - West Coast, Southland, Marlborough, Nelson, Gisborne, Manawatu-Whanganui, Taranaki and even Wellington.
West Coast is the only region tipped to decline under the medium-growth projections, losing 200 people a year when deaths start outpacing births in the early 2030s and 900 a year in the 2040s. The culprit? An ageing population.
"An ageing population means we can expect more deaths, despite increasing life expectancy, so population growth will generally slow in the long term," said Slack.
Auckland, Waikato, Gisborne, Wellington, and Canterbury are the only regions expected to have more births than deaths by the 2040s - other regions will need to rely on people moving in if they're to keep their populations up.
"The total number of people who will be living in each area in the future is uncertain. However, what is certain is that every area of New Zealand will have more older people."