Consumer NZ is calling out "dodgy" supermarket specials after shoppers found hundreds of errors in grocery prices.

The watchdog received over 300 examples of misleading deals and pricing errors as part of its campaign launched in September to clean up supermarket pricing.

People reported 78 cases where the "special" did not save shoppers money, while in 54 instances customers were charged more than the shelf price.

Another 18 cases involved misleading multibuys where the products would have been cheaper if bought individually.

Chief executive Jon Duffy told Morning Report it was a systemic issue affecting Foodstuffs and Countdown supermarkets around the country.

"We don't necessarily think that supermarkets are deliberately going out to do this, but they have created processes that allow these regular errors to sneak through."

Despite a recent market review by the Commerce Commission which highlighted issues with incorrect pricing, Duffy believed supermarkets had not changed.

"The fact that they haven't introduced any innovation to, for example digitise their shelf pricing as we see in other jurisdictions, is an indication that they're not keen to invest in fixing this problem".

Supermarkets needed to stop making pricing errors because they were unfairly costing people money, Duffy said.

He said with the cost of living pressures on people at the moment, shoppers were looking for specials.

"They're really vulnerable to, if it's intentional, this type of misleading activity, [or] if it's accidental, this kind of negligent activity.

"Supermarkets need to realise when they make these mistakes it costs people money".

Duffy said the solution to misleading pricing was a new supermarket entity coming into the market, not engaging in misleading pricing, and offering an alternative for shoppers.

Countdown responds

Countdown said in a response it was committed to making sure prices in its supermarkets were clear and unambiguous.

Managing director Spencer Sonn publicly responded to Consumer NZ last month saying there are robust systems instore to ensure prices are accurate.

However, he admitted being concerned by Consumer NZ's statement that the most errors reported to them came from Countdown.

Sonn said it was simply not good enough for customers to see incorrect ticketing in stores and he had asked teams to prioritise further action on product pricing.

This includes commissioning an internal review into instore systems to see whether there are ways to reduce the risk of errors occurring.

Foodstuffs responds

Foodstuffs said it worked quickly to correct pricing mistakes and would always refund customers when they had been incorrectly charged.

Head of Public Relations Emma Wooster said Foodstuffs supported recommendations by the Commerce Commission to address pricing errors.

She said significant progress had been made in simplifying pricing and promotions within Foodstuff supermarkets.

According to Wooster, Consumer NZ had provided Foodstuffs with only seven examples of problem pricing in the past several months.

She said the majority of the seven examples appeared to be instances of differences between brand-wide prices and store specific prices but the customer received the best price at the point of sale.