Wellington, Sept 21 NZPA - Prime Minister John Key is to push international leaders gathering in New York for Wednesday's United Nations climate change summit to commit to helping agricultural countries get emissions down.

The event is organised by United Nations General Secretary Ban Ki-Moon to boost political will to act on climate change before a major meeting in Copenhagen in December.

At the December meeting more than 190 nations will meet to agree a broader successor to the UN's Kyoto Protocol, which obliges developed nations to cut emissions of greenhouse gases, mainly from burning fossil fuels, until 2012.

Nearly half of New Zealand's emissions are from agriculture.

"New Zealand can play potentially a leading role in scientific research in relation to greenhouse gas emissions from the agricultural sector," Mr Key told NZPA.

"We are probably better placed than almost any other country to lead that research partly because of our scientists and also the fact that we are a developed country with a large agricultural footprint."

It was unrealistic to ignore the issue of agricultural emissions and New Zealand wanted a global research alliance to focus on technological answers to the problem.

"Clearly if we are going to resolve some of the issues in climate change (the world) is going to have to work collaboratively."

The developing world would only play its part when it came to climate change if it was affordable.

More than half of Brazil's emissions were for agriculture and it was in the 20 percent range for China and India.

Associate Minister for Climate Change Issues Tim Groser, who attended a meeting of climate change ministers over the weekend, said agriculture had been treated as a poor cousin in climate change, but with the world's population expected to be 9.5 billion by 2050 food security was a big issue.

"New Zealand's got a very special role here in terms of emerging as one of the key food baskets for the Asian middle class."

Food security had to match up with climate change.

"We are trying to build up the international political case for a far greater political focus internationally on agriculture in the climate change context."

Pressure was building before Copenhagen which needed to make process after a decade of stalling after the Kyoto Protocol was established.

"We need a political breakthrough," he said.

"New Zealand's got to be there if it wants to be taken seriously, that's why the Prime Minister is going."

International agreements needed to change domestic policy to make a difference, he said.

"The real tragedy in this, with the honourable exception of the European Union, nobody did anything for almost a decade after Kyoto was signed off.

"Then everyone has been scrambling around dealing with the reality that in most cases countries are no where near their wonderful targets announced many many years ago."

New Zealand emissions had gone up but the country had benefited from an unexpected higher valuation of its forests ability to sequester carbon.

The Government intended to pass an amended emissions trading scheme before Copenhagen.

"New Zealand will be one of the very few countries that can stand up and say, `not only have we got a target but we've got a domestic policy framework in place to deliver on this,' and we didn't have that 10 years ago.

"We can always improve...but we are in a good place politically."