1L milk produced by Fonterra releases 940g of carbon dioxide

The Ministry of Agriculture & Forestry put $225,000 towards the study, which was undertaken by the University of New South Wales, Scion and AgResearch.

It found that a carbon footprint of 940 grams of carbon dioxide is created per litre of milk.

Some 85% of the greenhouse gasses were emitted on the farm, 10% during processing and manufacturing and 5% in distribution.

According to the Ministry for the Environment, New Zealand accounts for only 0.3 per cent of the world's greenhouse gas emissions but farm animals produce nearly one-third of its total emissions.

Barry Harris, chairman of Fonterra's sustainability leadership team, said the study provided an accurate picture of the greenhouse gas emissions of its major products sourced from New Zealand and would help target increased efforts to reduce them.

He said improved farming methods had already reduced emissions on farms and research was continuing into cutting methane production further, including changing the diets of cows and selective livestock breeding.

The ratio of the carbon footprint of 1kg of British milksolids to the carbon footprint of 1kg of New Zealand milksolids was about 4:3, she said.

According to Professor Caroline Saunders, director of Lincoln University's agribusiness and economics research unit, 2007 research showed the UK produced 34 percent more greenhouse gases per kg of milksolid, and 30 percent more per hectare of dairy farm.

These figures included methane and nitrous oxide emissions from the cows, and the British farmers had a higher level of reliance on concentrated feed and forage.