Export commodity prices rose 0.7 per cent last month in both world price and New Zealand dollar terms.
ANZ's commodity price index is up 26 per cent on a year ago, at its third-highest level and just 5.3 per cent off its peak last April.
The increase was broad-based with 11 of the 17 commodities the index tracks rising while four declined.
Skim milk power and aluminium both rose 3 per cent. In aluminium's case it was off a four-year low in July and it is still 40 per cent below its peak in July 2008.
Dairy products make up 44 per cent of the ANZ commodity index. Whole milk powder was up 2 per cent, and cheese and casein up 1 per cent, but butter fell 2 per cent.