Wage and salary earners' incomes rose 4.8 per cent at the median over the year ended June, but the increase reflected an ageing of the working population as well as higher rates of pay.
The median is the level at which as many people earn more as earn less.
Statistics New Zealand's annual income survey found the median weekly income from wages and salaries was $844, $38 or 4.8 per cent higher than in June 2012.
That outstripped the 3.5 per cent increase to $21.58 in median hourly earnings. Statistics NZ attributes the difference to there being a higher proportion of wage and salary earners aged 50 or older and a lower proportion aged 15 to 24, in line with the household labour force survey's finding that more young people are studying than a year ago.
The greying of the workforce also contributed to an increase of 23 minutes or 1.1 per cent in average hours worked per week. People in the 50-plus age group work on average six and a half hours longer a week than those in the 15 to 24 band.
The survey continued to find that the late 40s are the peak earning years.
To maximise the statistical odds for earning a high income it is best to be a male, European, university graduate aged between 45 and 49 and working in Wellington.
The median income for Maori is 15 per cent below the national level and for Pacific peoples 33 per cent below.
For households, median income from all sources rose 4.1 per cent from June last year to $1358 a week. The average income increased 3.3 per cent to $1550. For households consisting of one parent and dependants the median income was $640, $48 more than last year.
The average income for all people from all sources - wages and salaries, self-employment, government transfers, investment income and superannuation - is $737 a week, up $16 on a year ago.
FIRST Union general secretary Robert Reid said working families were still struggling with high living costs and low incomes.