By RNZ 

Stats NZ said food prices were 4.5 per cent higher in December compared to the same time in 2020. 

The increase in annual food prices was the biggest jump since September 2011, when it increased by 4.7 per cent. 

Stats NZ said the rise was mainly driven by the higher prices for tomatoes. 

Tomatoes have nearly doubled (99 per cent) in price in the 12 months from December 2020. 

"The weighted average price of 1kg of tomatoes increased from $3.33 in December 2020 to $6.61 in December 2021," Stats NZ consumer prices manager Katrina Dewbery said. 

Higher prices for tomatoes were partly offset by cheaper prices for kiwifruit, kūmara and avocados. 

At a more aggregated level grocery foods, such as eggs, milk and yoghurt had the biggest impact on annual food prices, increasing 4.5 per cent Stats NZ said. 

Restaurant meals and ready-to-eat food prices increased 5.1 per cent. 

Stats NZ said households spent more on grocery food than on restaurant meals and ready-to-eat food, meaning grocery good price movements had more impact on the food price index. 

At a month-on-month level, food prices increased 0.6 per cent in December compared with November 2021. 

There were higher prices for fruit and vegetables, restaurant meals and ready-to-eat food and grocery food.