The statistics show median income has increased from $24,400 to $28,500 but the figure has not kept pace with the inflation rate - calculated to be $28,694 to have the same purchasing power.
Financial commentator Bernard Hickey said the contrast between the median income and the sharp increase in those earning more than $70,000 suggested the gap between rich and poor was widening.
"The total number of people earning [$70,000 or more] is relatively few; their incomes have risen much faster than those at the bottom end ... it appears people on higher incomes have done much better," Mr Hickey said.
"Those people on higher incomes, the skilled workers in demand, have done much better. Those closer to the minimum wage, working in fast food or rest homes, haven't moved much at all."
A Herald analysis of the income figures show a 90 per cent rise in people earning between $70,001 and $100,000 - from 125,115 to 238,212 - and a 40 per cent increase in those bringing home between $50,000 and $70,000.
Of those earning more than $100,000 41 per cent live in Auckland, 19 per cent in Wellington and 12 per cent in Christchurch.
Women are a fifth more likely to have a degree than men, but women's incomes lag behind men's because women are still more likely to do more unpaid child-minding.
The median wage gap between men and women widened by $1000, with the income difference between the sexes increasing from $12,400 to $13,400. Men earn $36,500 and women $23,100, according to the median income figures, up from $31,500 and $19,100 respectively.
The number of women on six-figure salaries has doubled from 22,824 to 45,294 since the 2006 Census.
The Census also reveals New Zealand's Asian population is up from 355,000 people at the last Census in 2006 to 472,000, or almost one in every eight New Zealanders.
A quarter of the population was born overseas.
New Zealanders are getting older, with the median age up 10 years from 28 in 1981 to 38 today.
- additional reporting: Simon Collins
