Butter prices have come off the boil, falling 4.9 percent after a record run of four consecutive monthly rises.
Official figures show food prices fell by 0.8 percent in December when compared with the month before, due to cheaper fruit and vegetables, along with grocery products.
Butter prices fell to an average price of $5.46 for a 500g block.
That follows recent falls for the price of butter on the Global Dairy Trade auctions.
Tomatoes and nectarines were also cheaper, but Stats NZ points out that avocado prices are about double what they were this time last year.
Stats NZ spokesperson Matthew Haigh said supermarket specials led to last month's overall fall.
But he said on an annual basis, consumers were still paying more.
"The higher prices for dairy, fruit, and vegetables throughout the year meant consumers were still facing 2.3 percent higher food prices than last December," he said.