Kiwi dairy farmers could be forgiven for thinking that the decimal point was in the wrong place, when viewing the latest Global Dairy Trade auction results this morning.

Prices across the board in last night's auction leapt an incredible 15.0 per cent to an average US$4,231/MT.

It's the eighth increase in a row, and the eleventh out the last twelve auctions.

But, unbelievably, the news got even better for farmers from there.

The largest gain sprung from the crucial Whole Milk Powder (WMP) index, which has the biggest impact on Fonterra's Farmgate milk price and shot up 21.0 per cent to an average US$4,364/MT - the highest price for WMP since May 2014.

Skim Milk Powder - Fonterra's second biggest reference product - backed up a small gain in the last auction with a 3.5 per cent increase to an average US$3,302/MT.

Butter, the other reference product to make an unexpected but significant gain, lifted 13.7 per cent to an average US$5,826/MT, while Anhydrous Milk Fat rose 7.4 per cent to an average US$4,929/MT.

Amongst the other products on offer, Lactose increased 4.9 per cent rise to an average US$1,278/MT, and Cheddar followed suit - up 1.3 per cent to an average US$4,280/MT.

The only product to buck the trend, Butter Milk Powder fell 0.3 per cent to an average US$3,144/MT.

Product volumes again fell slightly on the previous auctions, which can be expected as New Zealand's dairy herd's collective lactation curve falls, with 25,554MT of product sold, attracting just 86 winning bidders.

Last month Fonterra lifted its 2020/21 forecast farmgate milk price range by 20c/kgMS to between $6.90 and $7.50.

The midpoint of the range, which farmers are paid, increased to $7.20/kgMS from $7.00.

Fonterra chief executive Miles Hurrell was also surprised by what he called the "crazy increase."

"I'm certainly excited for our farmer shareholders out there that's for sure," he told The Country's Rowena Duncum.

Whole Milk Powder's rise of 21 per cent was a "standout", and "getting towards levels that we haven't seen for quite some time," Hurrell said.

The results reflected strong demand from China, where consumption was still growing at around 7.5 per cent, against domestic milk in that market which was roughly 5 per cent," Hurrell said.

"[This] still leaves that delta there off a larger base than we've seen previously, which goes a long way to signalling that they need our products. So that's a positive."

New Zealand's "relatively stable" supply chain also helped, Hurrell said.

Hurrell wasn't surprised to see North America's absence from this auction, as they were "coming into a bit more milk this time of year," along with Europe.

"We're probably on the cusp of two seasons as we wind down the Southern Hemisphere and the Northern Hemisphere hasn't quite kicked into gear."

"So that doesn't surprise me so much. The surprise [is the] demand that came out of China in particular."

Hurrell wouldn't confirm whether the GDT's continuous positive run would result in a lift in forecast farmgate milk price range.