The ANZ Commodity Price Index fell for a third straight month in August, following nine consecutive months of rises, led by milk powder, logs and aluminium.
ANZ said the index fell 1.2% in August to 304.3 and is now down 2.5% over the past three months.
Twice as many commodity prices fell as rose in August, the bank said, representing the broadest range of commodities to fall since August 2010.
Milk powder, logs and aluminium led the drop, with each falling 6%. Wool, butter and skin prices dropped 4%, lamb prices 2%, and the price of cheese and sawn timber fell 1 %.
Prices for fruit, beef, seafood and venison rose with wood, pulp and casein prices unchanged.
ANZ said the price of milk powders have now fallen 16% since March, with whole milk powder down 18% and skim milk powder down 8%. Log and aluminium prices have both dropped 11% since respective peaks in May and April.
Meanwhile, ANZ said a month-on-month decline in the value of the kiwi dollar buffered the commodity price fall, resulting in the New Zealand dollar commodity price Index being unchanged at 200.3 in August. The main index is in US dollars.
(Updated with chart, link to Terms of Trade article)