A spokesperson for Foodstuffs New Zealand - which owns Pak'nSave, New World and Four Square brands - said it was difficult to comment specifically on the price changes without knowing exactly which items were compared.
"But what we can say is that Foodstuffs North Island and its store owner/operators are 100 per cent focused on providing the very best products at the best prices possible year-round.
"This is achieved by offering an extensive and ever-changing range of special deals ...
"Essential to competitive pricing is strong supplier relationships. This means paying suppliers a fair price as without a good quality, reliable supply of produce and grocery items we are unable to give our customers the products they require."
Pak'nSave Papamoa's owner-operator could not be contacted for comment.
A Countdown supermarket spokesperson said 80 per cent of its customers shopped with a Onecard which offered shoppers extra discounts on the usual full price.
Statistics New Zealand said food prices fell 0.1 per cent in December compared with November, but increased by 1.5 per cent on the same month in 2012.
On an annual basis, there were increases in dairy products such as fresh milk (up 9.4 per cent), cheese (up 7.7 per cent) and yoghurt (up 10 per cent), while fruit rose 2.4 per cent.
Tauranga Budget Advisory Service co-ordinator Diane Bruin told the Bay of Plenty Times Weekend there had been an influx of people seeking budgeting help this month.
"Food prices have gone up slightly, especially fruits and vegetables," she said.
"Some fruits may have come down in price but other things are quite expensive which means people have to allow more money in their budget for the increase in their grocery bill. It's not easy for families with growing teenage children, and people need to shop around."
Mrs Bruin said a recent Otago University study found the average family of four, which included a teenage boy, should allow $260 a week for their groceries.
It was not only important for people to shop around but to save a lot of money she recommended they plan a week of meals, shop accordingly and stick to the shopping list.
She suggested people buy home brands rather than more expensive brand-name products and take advantage of discount vouchers and/or loyalty cards.
A new Oxfam report, Good Enough to Eat, said New Zealand had fallen well behind Australia and most of Europe in rankings of the healthiest and affordable places to eat in the world.
The cost of food and unhealthy eating habits had pushed New Zealand down the list to 23rd equal with Israel and well behind Australia, which was eighth equal.
