While this is the largest increase in a single month since July 2011, food prices often rise in January months.

"In January, higher food prices reflected more expensive grocery food, after falls in recent months. We also had seasonally higher fruit and vegetable prices," prices manager Chris Pike said.

The rise for grocery food (up 1.9 per cent) was led by cakes and biscuits (up 5.4 per cent), yoghurt (up 9.0 per cent), and bread (up 2.3 per cent). Olive oil (down 17 per cent) was discounted in January and was at its lowest price level since December 2002.

The monthly rise for fruit and vegetables (up 3.5 per cent) was led by seasonally higher prices for mandarins (up 23 per cent), apples (up 7.7 per cent), lettuce (up 20 per cent), and broccoli (up 38 per cent).

Apple prices were at their highest level since December 2008. Falls for nectarines (down 23 per cent) and pumpkin (down 13 per cent) partly countered these rises.

Price rises for meat, poultry, and fish (up 2.2 per cent) and non-alcoholic beverages (up 2.2 per cent) were influenced by less discounting for lamb (up 25 per cent) and soft drinks (up 3.6 per cent).

Annual Changes in Price

For the year to January 2013, the food price index (FPI) increased 0.8 per cent.

Fruit and vegetables (up 5.9 per cent) made the main upward contribution for the year, led by kumara (up 98 per cent), apples (up 21 per cent), and avocados (up 86 per cent). High kumara prices were influenced by poor weather conditions in both the planting and harvesting seasons, which affected the crop in 2012.

There was a smaller crop for avocados in 2012, after a bumper season in 2011. Meat, poultry, and fish prices increased 1.9 per cent, largely due to chicken, which increased 9.6 per cent from a low point in January 2012.

Grocery food (down 1.5 per cent) was the only subgroup that decreased in the year to January 2013. Decreases in the prices of fresh milk (down 9.4 per cent), cheese (down 6.0 per cent), butter (down 18 per cent), and bread (down 2.4 per cent) were the key influences. Fresh milk prices were 9.6 per cent lower than in February 2011, when they peaked.

The FPI measures the rate of price change of food and food services purchased by households. Statistics NZ visits shops across New Zealand to collect prices for the FPI and check package sizes.