Prices of dairy products extended their slide in Fonterra's latest GlobalDairyTrade auction, reaching the lowest since August 2009.

The GDT-TWI Price Index fell 2.4 per cent compared to the last sale two weeks ago. The average winning price dropped to US$2,843 a metric tonne. The price of whole milk powder declined 2.2 per cent to US$2,776 a tonne and skim milk powder fell 4.6 per cent to US$2,730 a tonne.

The decline comes as Fonterra's farm gate pricing faces political scrutiny in New Zealand, where the cooperative's enabling legislation is getting its biggest overhaul since the world's biggest dairy exporter was created in 2001. Among changes are greater regulatory oversight of prices and the promotion of Fonterra's Trading Among Farmers scheme that seeks to solidify its capital base.

Anhydrous milk fat dropped 13.6 per cent to US$2,852 a tonne in the latest auction. Cheddar gained 3.1 per cent to US$2,940 a tonne and milk protein concentrate declined 11.7 per cent to US$3,990 a tonne. Rennet casein fell 0.5 per cent to US$6,395 a tonne.


Lactose, which is sold by Australian dairy company Murray Goulburn, rose 3 per cent to US$2,016 a tonne.

There were 119 winning bidders over 11 rounds, out of 136 participating bidders. The number of qualified bidders rose to 620 from 610.