Shelly Fischer, who co-ordinates the Rotorua Salvation Army food bank, said many people still struggled with high grocery prices.
Specials at the supermarket could also trap families into unnecessary spending.
"When you get the specials like 'buy two packets for five dollars', that's not really a special. If you'd only normally buy one packet, you're actually spending more."
Consumer NZ chief executive Sue Chetwin said the secret to Countdown's rise to second place was its numerous discounts and multi-buys.
"Some of the discounts were huge - you could save $2.49 on a pack of instant coffee."
Getting good deals at Countdown was about sticking to specials, she stressed.
For example, tea bags bought on special from Countdown as part of the survey were discounted by $1.10.
Shoppers after the same brand of tea bags at Pak'n Save or New World had to pay at least $1.10 more.
Despite this, Countdown was rated the most expensive for online shopping in Wellington, with items costing $160 including a $13.25 delivery fee.
When online shoppers picked up groceries, they saved $8 according to the survey - dropping the online Countdown bill below its New World Wellington city rival.
Dunedin Pak'n Save was awarded New Zealand's supermarket minnow title, coming out with the lowest grocery bill in the survey ($126).
The chain was also the cheapest for basic items like sugar, milk, flour and butter, with the lowest prices for seven out of the 10 basic items surveyed.
Chaffers New World in Wellington was the most expensive, with a bill of $157.
The 40 items rated included food and non-alcoholic drinks, personal care and cleaning items. Fresh meat, fish or produce were not included in the survey. Alcohol and wine were also excluded.
Smart shopping
Take a list and stick to it - avoid impulse buying.
Join the store's loyalty programme - Fly Buys or One Card - to make the most of deals and rewards.
Check the unit price as smaller size items can sometimes be cheaper than bulk buys.
Buy "house brands", such as Home Brand, Pams and Budget, for basics like milk, sugar, butter and flour.
Source: Consumer NZ