Dairy product prices fell at the Global Dairy Trade auction, declining for the third time in four auctions, amid concern about extra supply.

The GDT price index slid 1.6 per cent from the previous auction two weeks ago to US$3,343. Some 32,768 tonnes of product was sold, up from 26,688 tonnes at the previous auction.

Whole milk powder rose 1.3 per cent to US$3,155 a tonne.

"The market struggled to absorb the extra volume of product available on GDT which does not bode well for the coming months when offer volumes continue to lift in line with the seasonal lift in New Zealand's milk supply," AgriHQ dairy analyst Susan Kilsby said in a note.


At the latest GDT auction, butter fell 4.9 per cent to US$5,747 a tonne, while anhydrous milk fat dropped 4.9 per cent to US$6,289 a tonne.

"While milk-fat prices fell at the latest GDT event, they are still quite high historically," Kilsby noted. "The falls in the price indices at the August 1 event do indicate that buyers are starting to resist paying such high prices for milk fats."

Cheddar fell 4.8 per cent to US$3,932 a tonne, while rennet casein declined 4.4 per cent to US$6,122 a tonne.

Lactose retreated 4.3 per cent to US$787 a tonne, while skim milk powder decreased 3.0 per cent to US$1,966 a tonne.

Bucking the trend, butter milk powder rose 0.4 per cent to US$2,198 a tonne.

The New Zealand dollar last traded at 74.77 US cents at 2.30pm in New York, compared with 75.12 US cents at 5pm in Wellington the previous day.

There were 129 winning bidders out of 162 participating at the 14-round auction. The number of qualified bidders fell to 521, down from 525 at the previous auction.