"This is the fourth consecutive decrease in the whole milk powder price index, with price levels decreasing across all contract periods, particularly for June and July deliveries," NZX dairy analyst Robert Gibson said in a note.
"Although offer volumes leading into the event were unchanged on the previous event, prices likely reflect buyers having adequate short term cover, with milk supplies coming online in the Northern Hemisphere," according to Gibson.
At the latest GDT auction, butter retreated 3.2 per cent to US$5,297 a tonne, while anhydrous milk fat slid 1.4 per cent to US$6,140 a tonne.
Meanwhile, cheddar soared 15.2 per cent to US$4,851 a tonne, while rennet casein jumped 5.1 per cent to US$6,916 a tonne.
Lactose rose 0.6 per cent to US$893 a tonne, while skim milk powder gained 0.5 per cent to US$2,529 a tonne.
The increase in skim milk powder prices "was driven by demand for contracts for August to November, likely in response to markets anticipating New Zealand spring milk production," Gibson noted, adding that the increase in the overall average price occurred despite offer volumes being up on 17 percent on the previous event.
Butter milk powder was not offered at this event.
For sweet whey powder, no product was offered or sold, or no price was published for the last event, or on both of the two previous events.
The New Zealand dollar last traded at 65.05 US cents as of 3.24pm in New York, compared with 65.34 US cents at the previous close in Wellington.
There were 100 winning bidders out of 149 participating at the 20-round auction.
The number of registered bidders was 524, down from 529 at the previous auction.