Gaps between rich and poor areas of Auckland are widening, even though almost all areas are getting at least slightly richer.

A new set of maps of Auckland published yesterday by Statistics New Zealand shows the median income of employed people in areas that have tracked the regional average, such as Pt Chevalier South, rose by 14 per cent in the 15 years to 2006 in real terms, after adjusting for price inflation - from $32,600 to $37,300.

But real incomes rose much faster in the richest areas such as St Mary's Bay (up 39 per cent to $55,300) and St Heliers (up 30 per cent to $53,900).

At the other end of the scale, the median income in Otara North rose by 3 per cent in real terms over the 15-year period, from $25,100 to $25,900.

The maps are based on 388 suburbs, mostly with populations of 3000 to 5000 people.

Income figures include everyone working at least one hour a week.

They show that areas with median incomes above about $40,000 have spread over the 15 years from small areas of central Auckland and pockets around Paremoremo, Titirangi, Howick-Pakuranga and Totara Heights in 1991 to include virtually the whole of the east coast from Whangaparaoa to Maraetai and large rural areas to the north, west and south.

The richest area is now Gulf Harbour Marina on the Whangaparaoa Peninsula with a median income of $60,000, more than twice the poorest area, Great Barrier Island ($25,100). Otara North is the second-poorest.

The figures also show a big increase in ethnic diversity over the 15 years.

The proportion of Europeans has dropped from 76 per cent to 64 per cent and Asians are up from 6 per cent to 19 per cent. Asians make up more than a fifth of the population in inland parts of the North Shore, most of the southern half of Auckland City and large parts of Manukau.

The number of areas where more than a fifth of the population is Maori has declined. Maori are now most concentrated in Papakura (27 per cent) and parts of Manukau.

By 2006, 37 per cent of all Aucklanders were born overseas, compared with 23 per cent of the New Zealand population as a whole.

Projections to 2031 suggest all parts of the region will have big increases in the elderly as the population aged 65 and over rises from 133,800 at the 2006 Census to a forecast 329,300.

The biggest increase in the elderly will be in Manukau (up 183 per cent to 81,300), but Rodney District will have the highest proportion of old people (23.8 per cent, up from 15 per cent now).