New Zealand's Green Party is disputing claims by the government over what carbon emission targets it can achieve.
This week at the Pacific Forum summit in Cairns, small island states called for New Zealand to cut carbon emissions by 45 percent by 2020 - about double the target that Wellington has indicated it can meet.
The Green Party disagrees with government claims that its international commitment can only be met by purchasing carbon credits.
The Party's co-leader Russel Norman says New Zealand could reduce emissions by 40 percent through a series of reforms in the forestry, transport, energy and agricultural sectors.
"Often the National government uses the word sustainable not to do anything with the environment - they just mean that GDP keeps growing. Whereas I think what we really need to do is look at sustainable in terms of the environment. Increasing energy efficiency, I think, is a complete no-brainer. It means that out appliances, our fridges and so forth use less electricity which costs us less money and we reduce our greenhouse gas emissions. Why on earth would you not do that?"