The claims are part of a high court case being brought by a rival.

A2 Milk Corporation is producing a new type of milk, one without the protein, linked by research, to heart disease, diabetes and mental disorders.

Milk is a symbol of goodness but a high court document claims that the public has not been told the whole truth.

It cites a dairy board briefing paper two years ago which states: "If the media were ever able to assemble the information shown in this paper they could put an alarmist spin on the whole area of milk consumption."

"We think the Dairy Board has had information that they should have acted upon and didn't" Jim Guthrie Chairman of A2 Milk Corporation says.

Guthrie, the chairman of the company that is producing a new kind of milk, says that A2 does not have the protein present in normal A1 milk which some research has linked to heart disease, diabetes and mental disorders.

The dairy board admits in the briefing paper: "...The contents of this briefing paper could form the basis for an argument for the production of A2 milk for at risk individuals."

But Fonterra says that paper is well out of date.

As far as we are concerned there is no evidence at all linking the drinking of milk with any of the health disorders that A2 allege," Chris Mallet of Fonterra says.

A2 wants the high court to order Fonterra to place a health warning on all the milk the public buy but the legal battle may well be more about marketing than anything else - A2 expects to have its milk on supermarket shelves by the end of the year.

Most New Zealand cows produce A1 milk, but thousands of cows are now being selected to produce A2.

Fonterra says A2's claims should not put people off normal milk.

"We think its irresponsible because it neglects the very substantial health benefits it brings to people who consume it," Mallet says.

Fonterra says it will fight hard in court to protect its key product.

Source:  ONE News sourced from TVNZ, RNZ, Reuters and AAP.