The Green Party is proposing a split-target for reducing greenhouse gas emissions.
The Government is about to start a round of public meetings on setting a target to reduce the country's emissions by 2020.
It intends to table the target at a round of international Climate Change negotiations in Germany in August.
The European Union says it will cut emissions by 20% of 1990 levels by 2020, and by 30% if other developed nations follow suit.
Greenpeace wants New Zealand to set a 2020 target of at least 40% below the level in 1990.
Green Party co-leader Meteria Turei used Question Time in Parliament to propose a target of 40% for transport, energy and industrial emissions, and a target of 20% for livestock emissions.
Climate Change Minister Nick Smith told Parliament that he's open to the idea.