The trial is happening at Foodstuffs North Island stores.
Consumer NZ says it's best to shop around.
The latest grocery data showed an increase of 5.4 percent in October, but it's the slowest rise in 19 months.
"It's a $25 billion industry, it's a big industry to get involved in."
The latest grocery data showed a 6.6 percent rise in August.
July was the fifth month in a row that monthly costs of groceries rose roughly triple the rate of pre-pandemic prices. Video description: Olsen didn't paint a rosy picture with supply costs continuing to rise.
"This is a serious issue you need to get your act together. So it is disappointing to see it still coming up."
"He'll make no difference, just a lot of talk."
Price pressures could soon start to ease.
