Rennet casein prices fell 11 per cent to US$10,533 a tonne and anhydrous milk fat dropped by the same amount to US$4,578 a tonne. Whole milk powder, the biggest product sold by volume, fell 5.8 per cent to US$4,439, its biggest decline since June last year.
The auction comes ahead of government figures which are expected to show New Zealand's annual current account deficit narrowed to $7.41 billion in the three months ended December 31 from $8.77 billion in the September quarter. The country's terms of trade are at a 40-year high and have helped underpin the local export sector, with massive Chinese demand for dairy products.
Skim milk powder prices fell 1.7 per cent to US$4,584 a tonne, the first time it's been more expensive than whole milk powder. Butter prices fell 4.4 per cent to US$4,534 a tonne.
Butter milk powder prices were the biggest gainer, up 4.6 per cent to US$5,253 from the last auction, followed by a 3.7 per cent gain in milk protein concentrate to US$8,837 a tonne. Lactose wasn't offered at the event.
There were 142 winning bidders of 187 participating bidders at the auction over 10 rounds. The number of qualified bidders fell to 747 from 796 at the last auction.