Contribution of 65+ Years to Total Change

Several research projects have noted that close to 60 per cent of New Zealand’s population growth over the next 25 years will be accounted for by those aged 65+ years (medium variant) (e.g., Jackson and Cameron 2016; Jackson and Brabyn 2017).

The impact will be even greater in the short to medium term, with those aged 65+ years accounting for over two-thirds of national growth (medium variant) between 2018 and 2038. Under the high variant assumptions, the proportion would be lower, at 47 per cent, while under the low variant assumptions, those aged 65+ would account for 146 per cent of growth. Whichever scenario prevails, these are sizeable impacts.

At territorial authority area (TA) level, where population ageing has its local impact, the trends tell an even more profound story; one of disproportionate growth at 65+ years either offsetting, or failing to offset, decline at most younger ages—in the latter case leading to overall depopulation. Under the medium variant assumptions, only 14 TAs (21 per cent) are projected to experience growth at both 0-19 and 20-64 years in addition to that at 65+ years, over the next 20 years.

These maps illustrate the trends at TA level for the period 2018-2038, broken down into the two decades 2018-2028 and 2028-2038. Data are provided under Statistics New Zealand’s high, medium and low assumptions. Blue colours indicate overall decline (depopulation), reds and yellows indicate growth, each shade illustrating the relative role of growth at 65+ years vis-à-vis change at 0-19 and 20-64 years.

Medium Variant: Between 2018 and 2038, all growth in 46 TAs (over two-thirds of all TAs) is projected to be at 65+ years. Around 18 of these TAs are projected to experience overall decline in size, while two to experience zero growth, despite the growth at 65+ years. The remaining 26 TAs in this group are projected to grow, but only because the growth at 65+ years offsets decline at both 0-19 and 20-64 years. A further seven TAs are also projected to grow, with the growth at 65+ years augmented by growth at 0-19 years, offsetting decline at 20-64 years of age. As noted above, only 14 TAs see growth across all three broad age groups.

The period 2028-2038 will see the greatest impact. Across that period, 26 TAs (39 per cent) are projected to decline under the medium variant assumptions. In 25 of these, growth at 65+ years is substantial, but fails to offset decline at 0-19 and 20-64 years; in just one, there is also decline at 65+ years. A further three TAs experience zero growth, despite substantial growth at 65+ years. In an additional 18 TAs, growth at 65+ years offsets decline at 0-19 and 20-64 years to deliver overall growth, bringing to 47 (70 per cent) the number of TAs reliant on growth at 65+ years to either reduce the extent of overall decline, or grow modestly despite decline at 0-64 years. A further 10 TAs are projected to have growth at either 0-19 or 20-64 years in addition to 65+ years, and thus to grow—but primarily because of the growth at 65+ years (i.e., no other age group approaches the magnitude of growth at 65+ years). Only 10 TAs (15 per cent) are projected see overall growth that is underpinned by growth across all three broad age groups—but again, disproportionately at 65+ years.

These trends have significant implications for a broad range of policies and policy development that must urgently take account of, and be oriented towards, subnational diversity. Among these considerations for example must be local government rating frameworks. The ageing-driven growth of the 21st Century is very different to the youth-driven growth of the 20th Century. Whether population growth is achieved solely by growth at 65+ years, or depopulation occurs but is reduced by growth at 65+ years, the overarching reality is that those over 65 years will not be able to underwrite the increases in rates that will be needed going forward. Only a handful of TAs sit outside these realities.

Contact – Natalie Jackson (

References and further reading

Jackson NO and L Brabyn (2017) ‘The mechanisms of subnational population growth and decline in New Zealand, 1976-2013’ Policy Quarterly Supplement 13: 22-36.

Jackson N and MP Cameron (2018) ‘The unavoidable nature of population ageing and the ageing-driven end of growth - an update for New Zealand’ Population Ageing 11: 239.