Dairy commodity prices tumbled at Fonterra's overnight online auction, with the globalDairyTrade trade weighted index falling 8.2 percent, and the average winning price down to $US4443 ($NZ6064) from $US4826 a fortnight ago.
The decline came amid a broad sharp fall in commodity futures, with the Reuters-Jeffries CRB index on course for its biggest daily slide in four months on fears Japan's nuclear crisis could turn into a larger catastrophe.
At the Fonterra auction, the trade weighted price for anhydrous milk fat fell 4.5 percent to $US6111, skim milk powder fell 4.6 percent to $US3816, and wholemilk powder dropped 11.4 percent to $US4105.
BNZ said the decline was broadly as expected, and prices were still up 17.5 percent for the year and likely to stay at favourable levels for some time.
