Auckland's three main ethnic groups of Europeans, Asians and people of Maori and Pacific heritage could all be of roughly equal size in 40 years if population trends continue, an expert says.
Professor Charles Crothers of Auckland University of Technology said Europeans could shrink from 66 per cent of Aucklanders at the 2006 Census to 36 per cent by 2051.
Asians could rise from 19 per cent to 35 per cent, and those of Maori or Pacific ethnicities could increase slightly from 25 per cent to 29 per cent.
But the figures he gave at a Population Association conference yesterday were not directly comparable with the 2006 data because he did not allow for people with multiple ethnicities in 2051.
About 10 per cent of people in the 2006 Census identified with more than one ethnicity.
The Auckland Council's draft plan for the next 30 years projects an increase of about 700,000 in the region's population, from just under 1.5 million at present to between 2.2 million and 2.5 million by 2041.
An ethnic breakdown projected just 10 years out shows the European population dropping to 53 per cent, and the Asian share rising to 27 per cent, by 2021 - a change in the ethnic balance which came under fire in a recent Grey Power submission to the council.
Statistics NZ does not project ethnic populations by region beyond that because of the extreme uncertainty involved, but Professor Crothers took the current projections and extrapolated them out to 2051.
"At that stage, if those projections have any bearing at all, we would be roughly one-third Pakeha, one-third Asian and one-third Maori/Pacific."
Grey Power member Bill Rayner, who wrote the submission to the council, said from the floor of the conference that his concerns were based on language.
"People from the old English colonies such as Singapore, Malaysia and Hong Kong can speak English and can integrate much better than people from North China, where they have no real cultural linkage with New Zealand," he said.
Professor Crothers said the issue needed more study. "I don't see why there shouldn't be a royal commission on it."
Auckland Council social researcher Alison Reid, the Population Association's president, stressed that projections were based on specific assumptions and were not forecasts of what would actually happen.
But she said all the projections showed that Auckland's population would keep growing faster than the rest of the country.
Proportionately, she said, the biggest growth in the next 20 years to 2031 was projected in the central city Waitemata local board area (up 89 per cent or 59,200), and in the Upper Harbour local board stretching from Whenuapai to Albany (up 86 per cent or 38,600 people).
The Howick local board area, which already had the biggest population of any board in the 2006 Census (113,500), also has the biggest projected numerical increase, up 77,700 people or 65 per cent by 2031.
Population increases of between 21 per cent and 61 per cent are projected for all other local boards except Great Barrier Island.
Ms Reid said the rate of population increase would slow over the next 20 years.