Prime Minister John Key has defended the Government's decision not to sign on for the second stage of the Kyoto Protocol, saying the country is playing its part in combating climate change.

The climate change treaty's first commitment period expires at the end of the year and New Zealand expects to slightly exceed its target.

The treaty aims to curb international greenhouse gas emissions through binding national commitments but some countries have questioned its effectiveness.

New Zealand would be joining other countries in going following the "convention track", Mr Key said on TVNZ's Breakfast show today.


"Next year New Zealand will name a binding commitment to climate change - it will actually have a physical rate that we're going to hit - but instead of being what's called a second commitment period that is likely to run from 2012 to 2020, we'll be able to set our own rules around that," Mr Key said.

Most countries, including the United States and Canada had also committed to the convention track, Mr Key said.

The Prime Minister said he wanted to see a change to some of the rules that governed Kyoto, especially around land use.

"We are a tiny, tiny, tiny fraction of world emissions ... New Zealand needs to play its part, it is playing its part, it's already part of the emissions trading scheme and we've made quite a lot of other changes - we are there doing things about climate change. But I think we never wanted to be a world leader in climate change."

Mr Key said he needed to make sure climate change measures were not being prioritised over everything else.

"And I think we've got that balance about right."

Some 15 per cent of countries, including Australia, have renewed their commitment to the Kyoto Protocol.

Green Party climate change spokesman Kennedy Graham said New Zealand had committed only to producing hot air at talks by not agreeing to legally binding measures to reduce emissions.


"Not content to pass a law [on Thursday] to gut New Zealand's emissions trading scheme, the National Government is now out to undermine any international credibility the nation ever had on climate change."