Commodity prices have fallen for the fourth consecutive month, led by dairy prices.
The ANZ Commodity Price Index fell 11 percent for July compared with the previous month, to its lowest level in almost six years.
The index is down 26 percent compared with a year ago.
Thirteen of the 17 main commodities measured fell: dairy, which makes up nearly half the index, plunged 23 percent to its the lowest level in 11 years, while whole milk powder was down 35 percent.
Forestry prices fell by 2 percent, led by log prices, due to softer Asian demand, while aluminium, kiwifruit, apples, lamb, wool and skin all fell.
Prices for beef and seafood remained flat.