International dairy prices have fallen for the fourth consecutive time.
Prices fell by 3.5 percent, with an average price of $US2,515 a tonne, at the latest Fonterra global dairy trade auction.
A key price, that of whole milk powder, fell by 1.8 percent to $US2,386.
On the basis of previous falls Fonterra last week lowered its forecast payout to farmers for the current season, from $4.70 to $4.50 per kilo of milk solids.
The amount of product sold at last night's auction rose by 1773 tonnes to 27,369 tonnes.
Rabobank director of dairy research for New Zealand and Asia Hayley Moynihan said the fall in prices was largely expected because many international buyers had stocks of dairy products and demand was weak.