Cost of living: Grocery bills keep going up as food prices grow by 8.3 percent, Statistics NZ says

New Zealand's statistics agency's food price index rose again in August as cost pressures continue mounting amid global economic woes. 

Statistics NZ's index shows a food price increase of 8.3 percent in the year to August - the most in 13 years.

The index was also 1.1 percent higher (0.9 pct after seasonal adjustment) last month than in July.

Fruit and vegetable prices, up 15 percent year on year, represented a large chunk of the inflated food costs.

Stats NZ consumer prices manager Katrina Dewbery said eggs, yoghurt and cheddar cheese were the largest drivers of grocery food price increases. Grocery food, overall, soared 8.7 percent in the year to August.

Prices for meat, poulty and fish also rose by 7.6 percent in the same time period.

In other categories, there was also signifcant yearly increases in restaurant meals (up 6.5 percent) and non-alcoholic beverages (4.1 pct).

The data also showed a 2.3 percent seasonally adjusted month-on-month increase for fruit and vege prices.

"Vegetables had the largest impact on this monthly rise, influenced by higher prices for tomatoes, capsicums and cabbage," Dewbery said.

Food prices have been pushing up throughout this year, partly driven by the impact of Russia's invasion of Ukraine. 

Analysis earlier this year showed New Zealanders had on average spent an extra $4000-$5000 in the previous 12 months on basics including food, rent and fuel.

Infometrics principal economist Brad Olsen said on Monday he expected supermarket costs to remain inflated.

Rising costs in New Zealand and abroad were putting pressure on suppliers, which was being passed on to consumers, he said.

"Sustained higher input costs are driving suppliers to pass on these higher costs," Olsen said in a statement. "The continued rise in both the number and scale of cost increases from suppliers to supermarkets underscores the continued mounting pressure on retail grocery price.

"The momentum in supplier cost pressures within New Zealand suggests that supermarket costs and broader inflation measures will remain elevated for now."