Global dairy prices at the latest Global Dairy Trade (GDT) auction fell 1.3 per cent to US$3487 in a discouraging start to the new season.
Whole milk powder (WMP) prices were down 1.1 per cent to US$3205, though regular grade WMP to ship in August was practically unchanged.
Analysts had been picking either flat or slightly declining prices because of higher volumes being offered, and because premiums of futures over previous GDT have shrunk.
Favourable weather saw a rise in Fonterra's milk collection in New Zealand by 3 per cent during April, but for the 2017-18 season from June to April, New Zealand farmers produced 2 per cent less milk than the year before.
The latest result contrasted with the final auction for the season last month when prices lifted 1.9 per cent overall to reach US$3637.
The most dramatic change in the overnight auction was seen in butter milk powder, which jumped by 17.7 per cent.
AgriHQ pointed out there was a greater volume of WMP on offer than had been forecast.
WMP volumes for the auction were lifted 7.6 per cent from forecasts.
Buyers bought more WMP than they did at the May 15 event, but they were unwilling to pay more for it.
Butter prices fell 3.5 per cent, anhydrous milk fat was down 1.7 per cent. Skim milk powder prices were up marginally, lifting 0.3 per cent.
Cheddar prices were down 3.6 per cent, lactose lifted 3.9 per cent and rennet casein prices rose 2.7 per cent.