Banana prices spiked 22 percent from July, to $3.51 per kilo. The previous peak was $3.23, in March this year.

"Banana prices were at their highest since the series began in 1949, reflecting a supply shortage from Ecuador. Over the last three years, Ecuador has overtaken the Philippines as the main supplier of bananas to New Zealand," consumer prices manager, Matt Haigh, said. "Kiwi households spend an average of $88 a year on bananas, making them the most popular fruit."

Seasonally adjusted fruit prices rose 3.2 percent, as the rise in banana prices was partly offset by lower prices for avocados (down 25 percent).

Seasonally adjusted vegetable prices rose 2.1 percent as winter price rises were higher than usual this month. Unadjusted vegetable prices rose 8.9 percent, influenced by higher prices for tomatoes (up 41 percent), lettuce (up 7.8 percent), and cabbage (up 57 percent). This was partly offset by lower prices for cucumber (down 26 percent).

Prices for grocery foods rose 0.7 percent, with higher prices for snack foods, cheese, and confectionery products. Cheese prices have rebounded with a 3.0 percent rise following a consistent drop in prices over the last three months.

Overall food prices increased 0.5 percent in the year to August 2016.