A stronger New Zealand dollar swamped further gains in world prices for export commodities last month.
ANZ's commodity price index rose 0.3 per cent in world price terms to a 10-month high, its sixth consecutive monthly gain.
But with the exchange rate rising 0.7 per cent against the US dollar, and 1.2 per cent on a trade-weighted basis, the ANZ index fell 0.5 per cent in New Zealand dollar terms, to be 10 per cent down on January last year.
Dairy products, which make up 43 per cent of the index, rose 0.4 per cent last month on world markets, led by skim milk powder and butter.
But beef prices fell one per cent and lamb prices edged lower by 0.25 per cent.