But while it might have been the cheapest, the survey found some downsides. Pak'n Save does not carry the wide range of brands and pack sizes found on the shelves of New World and Countdown.
Competition for second and third place was separated by about $5 between Countdown and New World - though New World beat its rival in five of the centres.
Prices varied by up to $23 between the cheapest and most expensive shopping baskets.
The most expensive regions were Napier/Hastings and Wellington - but the survey found the most expensive way to buy groceries was at www.countdown.co.nz.
Countdown's online store prices were compared to Wellington's walk-in stores and added up to just over $140, but delivery bumped up the cost by $13.25.
Consumer NZ's mystery shoppers hit the supermarkets last month and bought a list of 40 top-selling products, including food and drink, personal care and cleaning products.
The survey did not include fresh meat, fish, produce, wine or beer.
Cost of 40 items
$126 Pak'n Save Sylvia Park
$128 Pak'n Save Albany
$138 New World Mt Wellington
$144 New World Albany
$145 Countdown Mt Wellington
$146 Countdown Glenfield