Pak'nSave is no longer the undisputed home of cheap food.
A Consumer magazine survey showed those who want the cheapest possible groceries would be better off at Woolworths, Countdown and Foodtown.
The yellow barns' more upmarket rivals proved the best places in Auckland to shop for a basket of budget items.
Pak'nSave was the cheapest option in Wellington and Christchurch, beating its nearest rivals by less than a dollar a basket.
House brands are usually cheaper than named brands because they get basic packaging and little advertising.
They have grown more popular this year, as shoppers switched brands to trim rising grocery spending.
However, the recent survey showed not all supermarkets were equal when it came to cheap options.
The Consumer survey checked the prices of 15 staple items, including milk, bread, cheese, rice and wheat biscuits.
It left out popular brands like Weet-Bix and Wattie's Baked Beans, going for the cheapest brand on offer in each item. That meant buying Budget brand at New World and Pak'nSave, and Home Brand at Foodtown, Woolworths, Countdown, SuperValue and Fresh Choice.
When there was no house brand item available, the next cheapest item was picked.
In Auckland, Woolworths ($37.33), Countdown ($38.24) and Foodtown ($38.57) were the cheapest places to buy, followed by Pak'nSave ($40.11), New World ($40.36) and The Warehouse Extra ($41.51).
Pak'nSave was the cheapest in Wellington and Christchurch, where the same basket of goods cost $36.80 and $37.75 respectively.
Of the 15 supermarkets tested in the three centres, the most expensive was New World in Wellington's Wakefield St, where the basic basket cost $46.58.
Survey supervisor Bev Frederikson said the survey used house brands because they were "the cheapest deal you can get".
She said the one-off survey was inspired by the growing number of people switching to budget brands.
Ms Frederikson said Pak'nSave lost out because it did not have as wide a range of house brand items, forcing shoppers to buy the more expensive Pam's brand.
The Warehouse Extra, which does not have a house brand, could not compete with any of the big Auckland supermarket chains. It came sixth out of six Auckland supermarkets, with a basket cost of $41.51.
Progressive Enterprises' general marketing manager Elizabeth Higgs said sales of house brand products were outstripping sales of other ranges.
She said Progressive, which owns Foodtown, Woolworths, Countdown, SuperValue and Fresh Choice supermarkets, had had yearly sales growth in the double digits for most of its house brand products, and she expected the trend to continue.
Ms Higgs said the biggest savings for house brands came from the packaging, which was cheaper than rival products.
For those who want to include named brands in their weekly shop, Pak'nSave remains the cheapest supermarket.
A regular grocery survey of 40 popular items by Consumer magazine has named Pak'nSave the cheapest supermarket in all three main centres since 2002. The regular survey reflects national spending patterns, and includes popular brands like Coca-Cola and Weet-Bix.
Woolworths (Milford) $37.33
Countdown (Glenfield) $38.24
Foodtown (Glenfield) $38.57
Pak'nSave (Albany) $40.11
New World (Albany) $40.36
W'house Extra (Sylvia Park) $41.51