Almost half of all women and a third of men earn less than $18.40 an hour - a rate which two Labour Party leadership contenders have promised to implement as a "living wage" in the state sector if they win power.
A special breakdown of June 2012 income data, provided by Statistics NZ, also shows that part-time workers and young people are far more likely than others to earn below $18.40.
Would-be Labour leaders Grant Robertson and David Cunliffe promised this week to raise minimum wages for government employees and contractors to $18.40, which unions and church groups say is the minimum required to meet the basic needs of two adults and two children where one parent works fulltime and one half-time.
The current minimum wage is $13.75.
The figures show that the cost to go up to a living wage may be much less for the core public service than for the private sector. Only 15 per cent of the 114,000 people working in public administration and safety earned less than $18.40 an hour, the lowest share of all 14 industry groups.