Climate Change Minister Tim Groser is hitting back at criticism from scientists about the Government's decision not to sign up to the second round of the Kyoto Protocol.
New Zealand will instead make voluntary pledges under the UN Framework Convention on Climate Change, meaning the country will no longer have a legal obligation to reduce emissions.
Climate scientists say the Kyoto decision is a step backwards and contradicts growing momentum overseas to reduce emissions.
But Mr Groser said 85% of emissions come from countries outside of the Kyoto deal and the Government can do more by working through the Framework Convention.
"Kyoto is the past", he said. "The future rests on getting countries outside Kyoto to start doing something serious about climate change."
He said it would be wrong to tie the hands of a future New Zealand government for eight years while a single new treaty is negotiated.
Australia, one of the world's leading emitters of greenhouse gases, is signing up to the continuation of the Kyoto Protocol beyond 2012.
However other major economies, such as the United States, Japan, China, India and Russia, are not part of the protocol.
The protocol, initially adopted in Kyoto, Japan, in 1997, is aimed at fighting global warming by setting legally binding targets for countries to cut greenhouse gas emissions.
Discussions over a new legal deal covering all countries are due to begin in December and end by 2015, and the BBC reports the new deal would come into effect by 2020.