Federated Farmers says it's unrealistic to ask the agriculture sector to cut carbon emissions, because there were no alternatives.
The government is optimistic climate change talks in Paris this December will be successful.
It has pledged to reduce emissions to 30 percent below 2005 levels by 2030.
Biological emissions from dairy, beef and lamb farming make up 47 percent of the country's carbon footprint.
Federated Farmers national vice president Anders Crofoot said while the government was investing heavily in research, there were no real solutions yet to reducing bio-emissions.
Mr Crofoot said asking farmers to cut methane output was telling them to cut their production and, with rising costs, that was a quick way to go out of business.
He said one of the reasons the last climate summit failed was because of the mantra of all sectors, all gases.