Whole milk powder dropped 4.4 percent to US$2,210 a tonne, while anhydrous milk fat declined 2.7 percent to US$3,644 a tonne, and skim milk powder slipped 0.8 percent to US$1,890 a tonne.
The NZX Dairy Futures market had anticipated a lift in prices for both whole milk powder and skim milk powder from the December 15 auction, according to Handley.
Lactose climbed 11.4 percent to US$594 a tonne, butter gained 6.7 percent to US$3,314 a tonne, while rennet casein rose 3.9 percent to US$4,736 a tonne.
Cheddar added 3.5 percent to US$2,964 a tonne, and butter milk powder rose 1 percent to US$1,586 a tonne.
"Buyers have been less concerned about securing supply for later in the season than previously," Handley noted.
The New Zealand dollar last traded at 66.88 US cents at about 11am in New York, compared with 67.52 US cents at 5pm in Wellington the previous day.
There were 127 winning bidders out of 166 participating bidders at the 12-round auction. The number of qualified bidders rose to 616, up from 613 at the last auction