Subnational Population Estimates: At 30 June 2011

Commentary

This information release contains provisional estimates of the resident population of New Zealand's 16 regional council areas and 67 territorial authority areas at 30 June 2011. Population estimates give the best available measure of the size and age-sex structure of the population usually living in an area.

Earthquakes and international migration underpin local population change

Two factors had a major impact on local population change in the June 2011 year. Firstly, the 2010/11 Canterbury earthquakes triggered large migration flows as people were displaced from the earthquake-affected areas (primarily in Christchurch city and parts of the Waimakariri and Selwyn districts). Secondly, the number of international migrant departures (people leaving New Zealand permanently or long-term) increased. In total, there were 80,100 international migrant departures during the June 2011 year, 22 percent more than in the previous June year.

For some parts of the country, an inflow of people from the earthquake-affected areas contributed to an increase in net migration (the difference between arrivals and departures) and a higher rate of population growth in the June 2011 year. However, for many parts of the country, net migration decreased as an increase in international migrant departures was only partly offset by an inflow of people from the earthquake-affected areas.

New Zealand's population growth slows

New Zealand's population grew by 37,500 (0.9 percent) during the June 2011 year, compared with 52,000 (1.2 percent) in the previous June year. The reduced population growth was largely due to the increase in international migrant departures.

Population growth in the June 2011 year resulted from a natural increase (excess of births over deaths) of 33,600, and a net migration gain of 3,900. Historically, natural increase has made the main contribution to New Zealand's population growth. Over the last 40 years, natural increase accounted for about 80 percent of New Zealand's total population growth.

Christchurch city's population decreases after earthquakes

Christchurch city is one of New Zealand's 67 territorial authority areas. Prior to the 2010/11 Canterbury earthquakes, Christchurch city's population was growing. In the four-year period ended 30 June 2010, the city's population grew at an average annual rate of 1.0 percent, with population gains from both natural increase (2,200 per year on average) and net migration (1,600 per year on average).

The latest population estimates indicate that Christchurch city's population decreased by 8,900 (2.4 percent) in the June 2011 year. This population decrease was due to a net migration loss of 10,600, partly offset by a natural increase of 1,700.

Statistics New Zealand has used a number of data sources to assess population change in Christchurch city, and across New Zealand's subnational areas, during the June 2011 year (see Estimating local populations after the 2010/11 Canterbury earthquakes). Some of these data sources – including international migration statistics, electoral enrolments, health service data, linked employer-employee data, and school rolls – provide information that can be broken down by age. Collectively, they indicate that population change in Christchurch city was unevenly distributed across the age groups.

 Graph, Population change for Christchurch city, by broad age group, year ended 30 June 2010 and 2011.

During the June 2011 year, the population aged 0–14 years in Christchurch city decreased by 4,800 (6.9 percent), while the population aged 15–39 years decreased by 5,200 (3.8 percent). Factors contributing to this decrease included:

  • an increased outflow of young children and their parents
  • an increased outflow of young adults, who tend to be a highly mobile sub-group of the population
  • a decrease in the number of young adults moving to Christchurch city to study.

In contrast, the population aged 40–64 years and the population aged 65 years and over (65+) both grew slightly, up 300 (0.3 percent) and 700 (1.4 percent), respectively. However, their growth was lower than in the June 2010 year.

South Island districts grow fastest

Population growth in a number of South Island cities and districts accelerated as people relocated from the earthquake-affected areas. The five territorial authority areas with the fastest rate of population growth in the June 2011 year were the districts of Selwyn, Queenstown-Lakes, Ashburton, Waimakariri, and Hurunui. All of these districts are located in the South Island, with most close to Christchurch city. Eight other South Island territorial authority areas (including Tasman district, Nelson city, and Kaikoura district) also grew at a faster rate than the national average (0.9 percent).

A number of South Island areas had been growing quickly prior to the 2010/11 Canterbury earthquakes. In particular, the districts of Selwyn and Queenstown-Lakes have been New Zealand's fastest-growing territorial authority areas in recent years. They maintained this position in the June 2011 year.

 Graph, Fastest-growing territorial authority areas, year ended 30 June 2011.

North Island's population growth concentrated in main centres

Population growth in the North Island was largely concentrated in Auckland and the most populous cities. Collectively, four territorial authority areas (Auckland, Hamilton city, Tauranga city, and Wellington city) accounted for 81 percent of the North Island's population growth in the June 2011 year. These four areas accounted for 58 percent of the North Island's population at 30 June 2011.

Of the 43 territorial authority areas located in the North Island, 25 recorded a net migration loss in the June 2011 year and 39 had a lower level of net migration than in the previous June year. Eight North Island territorial authority areas recorded a population decrease in the June 2011 year. The largest rates of population decrease were in Ruapehu and Wairoa districts (both down 1.0 percent), and Kawerau district (down 0.8 percent).

 Map, Population change, North Island territorial authority areas, year ended 30 June 2011.

Map, Population change, South Island territorial authority areas, year ended 30 June 2011.  

Porirua city has highest percentage of people aged 0–14 years

Children aged 0–14 years comprised 20 percent of New Zealand's population at 30 June 2011. Of New Zealand's 67 territorial authority areas, Dunedin city had the lowest percentage of children (15 percent) while Porirua city had the highest (25 percent).

The territorial authority areas with the highest percentage of children at 30 June 2011 were all located in the North Island. All of these areas have fertility rates that are above the national average.

 Graph, Territorial authority areas with highest percentage aged 0 to 14 years, at 30 June 2011.  Graph, Territorial authority areas with highest percentage aged 65 years and over, at 30 June 2011.

Kapiti Coast district has highest percentage of people aged 65+

At 30 June 2011, 25 percent of the Kapiti Coast district's population was aged 65 years and over (65+), almost twice the national average (13 percent). Other territorial authority areas with a high percentage of people aged 65+ included the districts of Thames-Coromandel, Waitaki, Horowhenua, and Waimate.

Areas with a high percentage of older people generally have net migration outflows of young adults (aged 15–29 years) and net migration inflows of people aged 35–74 years.

During the five years ended 30 June 2011, the number of people aged 65+ has increased in all territorial authority areas. The latest subnational population projections indicate that this growth will continue over the coming decades.

Other features of population change for territorial authority areas

In the June 2011 year:

  • 58 of the 67 territorial authority areas experienced population growth
  • Christchurch city was the only territorial authority area in the South Island to experience a population decrease
  • Thames-Coromandel district was the only territorial authority area to record a natural decrease (an excess of deaths over births)
  • Wellington city's population exceeded 200,000 for the first time, reaching 200,100 at 30 June 2011.

Population growth in all regions except Canterbury

Of New Zealand's 16 regional council areas (regions), 15 experienced population growth in the June 2011 year. The fastest-growing regions were Auckland, Tasman, and Nelson. The population of these three regions all grew 1.6 percent, but there were contrasting drivers for their growth. Natural increase accounted for 65 percent of Auckland's growth, whereas population growth in Tasman and Nelson was primarily due to net migration.

 Graph, Regional population change, year ended 30 June 2011.

The population of the earthquake-affected Canterbury region decreased by 5,000 (0.9 percent) in the June 2011 year. This decrease was due to a net migration loss of 7,600, partly offset by a natural increase of 2,600.

There were contrasting changes within the Canterbury region. While Christchurch city's population decreased by 8,900 (2.4 percent), the remainder of the Canterbury region experienced population growth of 3,900 (2.1 percent).

Auckland region's population grows by 24,000

Auckland's population grew by 24,000 (1.6 percent) in the June 2011 year, accounting for 64 percent of New Zealand's population growth. In comparison, the population of the rest of New Zealand grew by 13,500 (0.5 percent) over the same period.

Auckland is New Zealand's most populous region and has been the fastest-growing region over the last decade. At 30 June 2011, 1 in every 3 New Zealand residents lived in the Auckland region.

Other features of population change for regional council areas

In the June 2011 year:

  • all 16 regions experienced population gains from natural increase
  • Auckland (8,400) and Otago (1,600) had the largest population gains from net migration
  • the population of the North Island regions grew by 37,300 (1.1 percent) while the population of the South Island regions grew by 200 (0.0 percent).

For more detailed data see the Excel tables in the 'Downloads' box.