The Household Economic Survey showed housing costs and utilities were the biggest household costs at $272, making up about a quarter of household bills on average.
Food costs made up one-fifth of expenses, costing $192 a week on average, up from $177 three years ago.
Darryl Evans, CEO of the Mangere Budgeting Service, said clients were spending a large portion on rent, with very little left for food.
About three-quarters of clients in private rentals were paying 60 to 65 per cent of their income on housing.
Among the service's clients, the average spend on food for a family of four was just $83, he said.
"Which is why a large number of our families are trying to survive on two-minute noodles, and trying to bulk it up with frozen peas and corn.
"The fact is a lot of families are absolutely struggling," he said.
Craig and Carla Bradley, the parents of three boys, were forced to move out of their Auckland home because they couldn't pay the rent and their car was repossessed.
Craig's job as a van driver and maintenance man at a Takanini kindergarten earns him $16 an hour.
Carla, 31, took a job as a teacher's aid for six months but found all her wages were being spent on childcare.
"I was getting $100 a fortnight, and it didn't really go anywhere," she said.
She said the couple sometimes skip dinner to feed their sons and they are living with friends in Papakura while awaiting the fate of a Housing New Zealand application.
The Household Economic Survey, which polled 3000 New Zealand households on their income and spending habits, showed spending was up 9.1 per cent on three years ago, while incomes were up by 11.5 per cent over the same period.
But other Statistics New Zealand data based on a broader range of sources showed incomes had not kept pace with spending in the past year. In the year to March 2013, national accounts statistics showed spending was up by 2.6 per cent, while incomes had risen by just 1.8 per cent.
- additional reporting Patrice Dougan
