While New Zealand's population is increasing at a rapid rate, it's also becoming increasingly diverse.

New statistics show the country's grown at its fastest rate ever between censuses, with half the population now living north of Taupo.

But there's also been a change to the median age and the demographics of ethnic groups, with Māori and Asian people now making up nearly a third of the population.

The European ethnic group, while still growing, has declined slightly as a proportion of the population because it did not grow as fast as the other ethnic groups.

Auckland is a true melting pot of nationalities, as shown in the census data. 

Forty-two percent of the usually resident population in Auckland were born overseas, up from 39 percent in 2013.

But, country-wide, New Zealand is more diverse.

• New Zealand Europeans are the largest ethnic group, making up 70 percent of the population. That's down from 74 percent from the last census
• Those who identify as Māori now represent around 17 percent, up from 14.9 percent
• Comparably, 15 percent recorded as Asian - a dramatic growth from 11.8 percent in 2013

And with the largest ever growth between censuses the population should pass another milestone within a year, reaching the 5 million mark in 2020.

• Half of New Zealand's population is north of Taupo
• Northland is the fastest-growing region - it's now home to 179,000, up 18.1 percent
• The Bay of Plenty also rapidly growing up, 15.2 percent to 308,000
• Waikato is up 13.5 percent to 458,000
• Auckland increased 11 percent to 1.5 million
• The West Coast is the only region to shed population losing 573 people

The median age for the country has also dropped from 38 to 37 years but Stats NZ says this is just a blip - the country will resume its trend of an aging population in coming years.

For those who want to make the most of their youth, Hamilton City has the youngest residents, with a median age of 32 years.

Thames-Coromandel is the most senior district, with a median age of 53.6.