Fonterra has slapped a mystery injunction on former board member Leonie Guiney, banning any media from "using, publishing or otherwise disseminating confidential information" provided by her.

The order, made on Friday in the Wellington High Court, names NZX Rural as first respondent, Guiney as second respondent and unnamed defendants as third respondents.

Guiney is a South Canterbury dairy farmer who was elected to the board in 2014, but last year was blocked from standing as a candidate for a second term. She later went public with her disappointment.

"I think I was a necessary antidote to 'group think' on that board; I was a constant reminder of who the co-operative owners are and the supply strength that could come from trusting them more. I believe some on the board found this uncomfortable," she said in a statement.

READ MORE:

* Election system could erode farmers' control of Fonterra, outgoing director says

* Fonterra fails diversity test says Equal Employment Opportunities Commissioner

In an email to shareholders, Fonterra's board said the urgent injunction was "to prevent the publication of what we believe to be leaked and misrepresented details of Board discussions, supplied to the media by a former Fonterra Director."



"It is deeply regrettable that we have been forced to take this step in order to protect the Co-op."



"On any board, confidentiality obligations are intended, in part, to encourage robust debate, dissenting views, and honest and frank discussions.



"It is not uncommon to have disparate views around a board table, in fact, that is a sign of healthy debate. We must be able to have those conversations on your behalf within the boardroom, not in the newspaper," the email said.

After Guiney's failure to be chosen for the board last year, the Equal Employment Opportunities Commission took Fonterra to task for reducing the number of women on the 11-person board to two.

Later at a public meeting Guiney said Fonterra's new election system created a risk to democratic control of capital.

"Farmers need to be confident the board is asking the same questions that they would if they had access to all the information that we have access to," she said.

Shareholders needed to be sure not to surrender their business sense for corporate slogans at governance level, Guiney said.

While Guiney served on the board, the dairy giant made some controversial decisions, including a $756 million investment for an 18.8 per cent stake in Beingmate, which it said would give access to the lucrative Chinese market for its infant formula and other products.

Following a troubled period during which Beingmate's share price has fallen and key staff have resigned, Fonterra's stake is worth about only $250m at current market prices.

In her decision, Justice Karen Clark said the injunction remained effective until the determination of the substantive matter, but any party could apply to revisit any aspect on 10 days' notice.