"This change is the result of strong demand for WMP over the next six months outside of the GDT events platform," Fonterra said.
Mike McIntyre, head of derivatives at Jarden, said Fonterra's move would be supportive of prices.
"The volume itself was not significant but I guess the sentiment was," McIntyre said.
"It suggests ongoing strong demand, which is consistent with the message that Fonterra has been giving all along," he said.
"It is a reiteration of what they have said over the past three or four months."
In late May, Fonterra announced an opening forecast for the 2021/22 season of $7.25 - $8.75 per kg of milksolids, with a midpoint of $8 per kg.
It also narrowed its 2020/21 forecast price range, with a $7.55 per kg mid point.
Chief executive Miles Hurrell said at the time the improving global economic environment and strong demand for dairy, relative to supply, had prompted the high 2021/22 forecast.
Jarden's McIntyre said the move to take product off the table would be supportive of an $8.00/kg milk price forecast.
Current New Zealand milk production is at a trickle as farmers prepare for the peak producing months of August, September, October and November.
"A lot of water is yet to go under the bridge but we obviously had a good end to last season, which puts us in good stead for this season," McIntyre said.
The next GDT auction is on Wednesday and futures pricing for the July and August WMP contracts is in the region of US$3900 a tonne.
The ANZ World Commodity Price Index continues to gain elevation, lifting 0.8 per cent, month on month, in June but dairy was the laggard, with very strong gains again recorded in the forestry sector.
In local currency terms the banks index gained 2.3 per cent, as stronger commodity prices were further boosted by the New Zealand dollar Trade Weighted Index easing by 1.1 per cent.
Dairy prices eased 1.5 per cent in June but remain 35 per cent higher than a year ago.
Most dairy products eased in price, with whole milk powder falling 2.1 per cent, month-on-month.
"It is not unusual for prices to soften at this time of the season as we start to sell high volumes of new-season product," ANZ said.
"Milk production in the US-has lifted, which means we are likely to see more non-fat dry milk (a product similar to skim milk powder) and cheese being offered on world markets," ANZ said.
"Overall demand for dairy products remains robust, but not strong enough for prices to be maintained at such lofty levels," it said.