Prices have fallen 8.3 per cent overnight in the latest online dairy auction, run by Fonterra.
The "gDT-TWI" index, which tracks average prices across different dairy products sold in the auction, fell by 8.3 per cent, evidence of "the market rebalancing amid increasing supply and an uncertain economic outlook", said manager Paul Grave.
It is the fourth consecutive month of auction price falls.
Skim milk powder prices were down 8.9 per cent and whole milk powder was down 7.7 per cent.
The next auction will be held on September 7. From September there will be two auctions run every month.
More information about the latest auction here.