Meanwhile, the number of people aged 50-69 years showed a large increase.
"The New Zealand population is aging, with the latest census results showing the median age of the population is 38 years, just over two years older than at the last census seven years ago,'' Government statistician Liz MacPherson said.
"As well as being older, the New Zealand population is also now more diverse, with an increasing Asian population, in particular.''
Almost one out of eight people living in New Zealand were Asian, up from about one in 11 in 2006.
Nearly two-thirds of Asian people, or 307,233, live in the Auckland region, where over one in five people are of Asian ethnicity.
This year's census was the first since 2006, after the Christchurch earthquakes disrupted plans to hold a census in 2011.
More than 5.6 million individual and dwelling forms were collected, with about 2 million of those completed online.
Today's release of key information would be followed by regular, detailed releases over the next 18 months.
The census results also show that Hindi is now the fourth most common language in New Zealand, after English, Maori, and Samoan.
The country's total number of dwellings, both occupied and unoccupied, increased by just over 118,000 since 2006, to top 1.7 million.
Nearly 30 per cent of this increase was in the Auckland region.
While there were more dwellings, a lower proportion of households owned their homes.
"The rate of home ownership fell to just under 65 per cent at the 2013 census, compared with almost 67 per cent at the 2006 census,'' Ms MacPherson said.
The number of unoccupied dwellings increased sharply since 2006, up more than 26,000 or 16.4 per cent.
"Almost 40 percent of this increase was in Canterbury, probably because of people leaving their dwellings after the 2010 and 2011 earthquakes,'' Ms MacPherson said.
The rate of home ownership in Canterbury was 68.3 percent - down from 70.4 percent at the last census. But the quake-hit region also had the second-biggest growth in median income in the country.
The census also showed people who had left Canterbury had mainly moved to the Auckland and Otago regions, Ms MacPherson said.
"Those who moved to Canterbury also mainly came from Auckland and Otago, and a large number came from overseas.''
The region had the fourth-highest percentage of overseas-born residents of all the regions, with 19.6 per cent, up 1.7 percentage points.
Of those, 27 per cent were Asian, giving the region the third-equal highest percentage of Asian people, on 6.9 per cent.
Census data released today also gave a snapshot of the country's Maori population, which was growing and youthful, although getting older.
One in seven people, or 598,605 in total, was Maori - up 33,276 or 5.9 or per cent on 2006. By comparison, the total New Zealand population grew 5.3 per cent.
"Maori are a youthful population, but as a group are growing slightly older. The median age of Maori in the 2013 census was 24 years - about one year older than at the last census,'' Ms MacPherson said.
The number of Maori aged under 15 continued to grow, but as a proportion of the total Maori population, decreased slightly since 2006.
The largest increase in the Maori population since 2006 was in the working-age group of 15-64 years, particularly those aged 30-64, followed by those aged 65 and over.
The census also showed more Maori were achieving formal qualifications at university.
More than 36,000 stated a bachelor's degree or higher as their highest qualification - a more than 50 percent increase since 2006.
Just over one in five Maori can now hold a conversation about a lot of everyday things in te reo Maori, a decrease of 4.8 per cent from 2006.
Statistics NZ also released regional census data today, which showed:
* Auckland had the highest percentage of overseas-born residents in the country, with nearly 40 per cent born overseas - well above the next closest, Wellington, where about 25 per cent were born overseas. Almost a quarter of Aucklanders, or 23.1 per cent, were Asian.
* Wellington had the highest median income of $32,700, almost 15 per cent higher than the national median of $28,500. It also had the highest percentage of people with degrees in the country - 28.1 per cent of people over 15, compared with the national average of 20.0 percent.
* The Bay of Plenty saw a drop in home ownership, down to 64.7 per cent from 67.3 per cent. Its overseas-born population increased 2.4 points to 17.3 percent - 39.8 per cent of whom were from the United Kingdom and Ireland, followed by Asia on 21.8 per cent.
* Gisborne had the highest proportion of te reo Maori speakers of any region, with 15.6 per cent able to hold a conversation in te reo. It also had the highest Maori population, at 48.9 per cent.
* Manawatu-Wanganui had almost 2800 more places to live, but home ownership was down to 65.2 per cent, a drop from 66.8 per cent in 2006, in line with national trends.
* Taranaki had some of the largest income growth since 2006, with the median income of people aged 15 and over increasing 25.4 per cent to $29,100, some $600 higher than the national median.
* Nelson had the third-highest percentage of residents who were born overseas, after only Auckland and Wellington. More than one in five, or 21.2 per cent, were born overseas, up from 18.6 per cent in 2006.
* Marlborough also saw an increase of 2.78 percentage points, with 16 per cent of residents born overseas.
* In Otago, there were about 5000 more occupied dwellings, but home ownership followed the national declining trend. The rate of ownership was 68 per cent, down from 69 per cent in 2006.
* Southland had the third-highest rate of home ownership in the country, on 69.7 per cent - but that was down from 73.5 per cent in 2006, and the largest regional fall in ownership.
* Northland had the second-highest proportion of Maori in the country, 32.4 per cent, and the second-highest rate of fluent te reo Maori speakers, 9.1 per cent. Both trailed Gisborne. French was the third most popular language in the region after English and Maori.
* Hawkes Bay mirrored the country's increasing diversity, with more Maori, Pacific, Asian and overseas-born people. Almost a quarter, or 24.3 per cent, were Maori, 4.4 per cent were Pacific, 3.6 per cent were Asian and 14.7 per cent were born overseas.
* Waikato has followed national trends in becoming increasingly diverse, with almost a fifth, or 17.9 percent, of the population born overseas. Of those, almost a third were from the UK and a quarter from Asia, with Waikato's overall Asian population at 6.9 per cent.
* Home ownership was highest in the Tasman region, with exactly three-quarters owning their own home, down slightly from 75.8 per cent in 2006. The drop was the second-smallest for any region after Nelson.
* The West Coast of the South Island saw the highest rise of median income in the country, with incomes increasing by 31.9 per cent since 2006. However, the median income of $26,900 was 5.6 per cent lower than the national median of $28,500.
