Dairy product prices have continued their slide in Fonterra's latest GlobalDairyTrade auction this week, reaching their lowest since August 2009.
Meanwhile, the price of sheep meat recorded the largest decrease in the ANZ commodity price index in April, falling 12% from a month earlier to an 18-month low.
The GlobalDairyTrade trade weighted index fell 2.4% compared with the last sale two weeks ago.
The average winning price dropped to $US2,843 ($NZ3494) a metric tonne.
The price of whole milk powder declined 2.2% to $US2776 ($NZ3411) a tonne and skim milk powder fell 4.6% to $US2730 ($NZ3355) a tonne, BusinessDesk reported.
The ANZ commodity price index also fell sharply in April, down 4.5% from a month earlier to sit at an 18-month low.
That represented the largest monthly percentage decrease in the index since February 2009.
Twelve commodity prices weakened in April, three were unchanged and two increased.
Wool prices dropped 9%, dairy and aluminium prices fell 6% and beef prices slipped 2%, while wood pulp and pelts lifted 4% and 5% respectively.
Economist Steve Edwards said international dairy prices had had "a roller coaster ride" over the past few years.
The surge over 2006-07 was due to an Australian drought restricting supply, combined with news of European countries phasing out export subsidies.
As a consequence of the global financial crisis and some fringe dairy exporting nations gradually increasing production, global prices fell back sharply.
An improvement in the world economy and renewed demand from China resulted in prices rising between 2009 and 2010.
Prices have recently slipped again, following weaker demand from China and increased production internationally.
Prices in the ASB New Zealand commodity price index were 1.8% lower in the week ended April 20.
The decline in meat prices in recent months had been largely driven by a correction in lamb prices from high levels, reflecting the reluctance of the United Kingdom and European markets to commit to large purchases.
With customers in those regions becoming increasingly price-conscious and used to purchasing at discounted prices during Christmas and Easter, New Zealand lamb producers were having a hard time shifting their products outside those holiday periods, the bank's commodities weekly said.
