Overall monthly commodity prices were up for the 11th consecutive month for January, but the dairy index recorded its first fall in seven months.
While the January 2010 figure was more than 33% higher than the corresponding month a year earlier, in New Zealand dollar terms the index was down by 1.2% because of the high kiwi.
The ANZ commodity price index for January recorded world prices up in seven index: skins 12%, logs 9.4%, beef 5.8%, aluminium 1.9%, lamb 1.8%, seafood 0.9% and sawn timber 0.5%.
ANZ economist Steve Edwards said dairy prices recorded the largest drop, of 2%, the first in seven months.
It was followed by wool which eased 0.6%.
"The fall in dairy is linked to the Fonterra [online, monthly] auction.
"It takes time for production to crank up," Mr Edwards said.
In early January, Fonterra's monthly globalDairyTrade internet auction saw whole milk powder prices fall 7% from the previous December sale, ending a five-month run in which prices had risen by 95%.
Mr Edwards said the strength of the New Zealand dollar against major trading partners had also "undercut" some index gains - having traded above at least US70c most of the month.
"This strengthening resulted in a drop in the commodity price index, of -1.2%, when valued in New Zealand dollars," he said.
Mr Edwards said strengthening economies overseas, such as China and other Asian countries, would likely underpin a future rise in commodity prices such as aluminium and sawn timber.
However, New Zealand was well placed with soft (food) commodities as those same economies increased imports of protein, he said.
