It was not surprising to see staple foods like bread, eggs, milk and fruit top the list, Retail NZ chief executive Greg Harford said.
"These are the items that Kiwis consume on a daily basis, and therefore get eaten quickly and purchased often," he said.
"There will be regional differences in the particular brands and products that people buy, but the key basic food items are broadly similar around the country.
"Occasional treat foods remain popular as well, and as a nation we love our pets, so pet food is also a big seller for many stores."
Over time there could be variance in the brands featuring in the lists, Harford said, but fresh products would always be king.
"Value for money is particularly important to customers at the moment, when there are pressures on household budgets."
Every week, about two million people shop at Foodstuffs supermarkets - 143 New Worlds, 57 Pak 'n Saves and 231 Four Squares.
About three million customers each week are served at Countdown's 182 stores nationwide.
Bananas were 2019's top food item for Countdown supermarkets. Photo / File
The difference in the products between the supermarket chains could be influenced by how consumers shop, said Chris Wilkinson, managing director of First Retail Group, a business consultancy.
"Brand association and the location of these supermarkets will be influencing factors.
"From the data, it's clear that Foodstuffs shoppers prioritise the 'must-haves' with meal components [like] eggs, bread, chicken etc.
"Countdown's customers have more of a discretionary spend, with 'nice to haves', like chips, chocolate, soft drink, capsicums and avocados in their top 10."
• The top products for Foodstuffs (New World, Pak'nSave, Four Square) were between grocery and frozen items. Meanwhile, the product units were for the entire store at Countdown.
