Fonterra says a study may help develop an international standard for measuring emissions by milk producers.
Results released from the 18-month project show each litre of milk produced by farmers generates the equivalent of 940gm of carbon dioxide.
About 85 per cent of the emissions occur on-farm.
New Zealand is a signatory to the Kyoto Protocol on climate change. About half the country's emissions come from farms and some of its exports have been targeted by UK environmentalists seeking special status for locally grown foods.
"We hope our work will speed efforts to agree a milk product carbon measurement standard that can be used by farmers and dairy companies everywhere," said Barry Harris, who runs Fonterra's sustainability project.
An agreed standard "means that if people want to make comparisons with other milk products or benchmark their performance, there is a fair and scientifically robust basis for doing so".
The study, audited by PricewaterhouseCoopers, was carried out by the University of New South Wales in Australia and research companies Scion and AgResearch.
Fonterra's manager for sustainable production, John Hutchings, said the methods adopted would contribute to work the Belgium-based International Dairy Federation was doing on a global carbon standard. He said that work was expected to be completed within a year.