"Our major concern is that [clients] aren't buying food for their families because they have got to pay their power bill ... it's a huge problem."
The service had seen a recent surge in clients, partly attributed to last year's Work and Income changes, she said.
"The cost of items is an ongoing problem, [so] we're educating people to go back to basics."
Mrs Gwillim said the service often advised clients to grow their own vegetables in an effort to counter price hikes and put healthy food on the table.
Inflation increased 1.6 per cent in the 2013 year, the highest annual rise since early 2012, Statistics New Zealand said last week.
International air fares jumped 12 per cent in the December quarter, while holiday packages rose 7.3 per cent.
Prices for housing and household utilities rose 0.5 per cent, while milk, cheese and egg prices jumped 4.2 per cent, the highest quarterly rise since September 2010.
However, these spikes were partly offset by a significant fall (20 per cent) in vegetable prices, particularly tomatoes, lettuce, and cucumber, which dropped about 50 per cent. Petrol prices fell 3.5 per cent.