Pak 'n Save has been hailed as New Zealand's cheapest supermarket.
The chain again scooped the Consumer NZ award, which it has dominated for the past 11 years.
This year Pak 'n Save was six to 10% cheaper than its nearest competitor in each of the seven centres surveyed.
The survey compared the price of a trolley of 40 identical items. This year's list had double the number of items from previous years, adding basic frozen food, spreads and canned food to the traditional basics such as bread, milk, sugar and butter.
Consumer NZ said the difference between the cheapest and most expensive Consumer shopping trolley was greatest in Christchurch at $24 and least in Auckland at $11.
The survey found that shopping around for milk was very worthwhile with buyers in Auckland and Wellington able to save over a dollar.
While Pak 'n Save was the winner on price, the survey acknowledges that some products or packet sizes are not available at the chain.
Competition for second and third places was extremely tight between New World and Countdown in the South Island, Wellington, South Auckland and Tauranga, with only a few dollars separating them.
New World was a clear second over Countdown in Auckland's North Shore but Countdown reversed this in Palmerston North.
Consumer says that grocery prizes rose 5.5% in the year to March.
Consumer tips for supermarket shopping:
Don't shop when you are hungry. With a full stomach you are less susceptible to the free samples and promotions designed to tempt you to buy more
Get to know your local supermarket layout so you can avoid temptations
Take a list and stick to it - it's the key to avoiding impulse buying
Join the store's loyalty programme such as Fly Buys or One Card to maximise discounts
Take advantage of multi-buys or stock up on good specials
Don't buy items just because they seem like bargains
Check the unit price - smaller items are sometimes cheaper than the larger size