The resignation of Fonterra chief executive Theo Spierings means chairman John Wilson can expect to "stay a little longer" in the job to ensure the stability of New Zealand's biggest company, says Federated Farmers.

Vice dairy chairman and Fonterra shareholder Wayne Langford said Wilson has "some potential life left" in the job to avoid a major impact on the cooperative, but he noted Wilson is up for re-election as a director by farmers later this year.

"The big question is whether or not he stands and then the board have got some big decisions to make about whether or not he will continue as their chairman.

A Fonterra spokeswoman could not confirm Wilson was due for rotational re-election this year, saying directors would not be announced until September.


Langford said Fonterra's announcement of a 15c/kg milksolids increase in forecast milk price to $6.55/kg would not be enough to soften farmer reaction to the half-year result or the loss over the Beingmate investment.

"While a payout rise is always positive and we can't downplay the massive result it has on New Zealand, farmers are still struggling with some poor decisions that have been made and I expect a strong turnout to the farmer-director meetings (post results) and some challenging questions."

Langford said the resignation of Spierings, announced after Fonterra's half-year financial results, was not surprising given he had been in the job seven years and succession planning for a chief executive should have been underway for some time.

"More surprising is the timing and what will get farmers wondering is whether it's related to the performance announced today."

Fonterra posted a net profit loss of $348 million and a $405m impairment on its $756m investment in China infant food company Beingmate. Fonterra also reported it had paid $183m to French company Danone in December following arbitration arising from product recalls over Fonterra's false botulism contamination scare in 2013.

Fonterra has about 10,000 farmer-shareholders.