Labour claimed its environmental policies launched yesterday were the greenest of all as it promised to bring farmers into the Emissions Trading Scheme by 2013 and make commercial users pay for water.
In Auckland, party leader Phil Goff and environment spokesman Charles Chauvel described the policies asthe "boldest" environmental pledges going in this election.
National amended the ETS to defer the inclusion of the agriculture sector until 2015. Labour estimates that revision along with others increased the taxpayer bill for New Zealand's greenhouse gas emissions by $50 billion to $110 billion out to 2050.
Under Labour's plans commercial water users - such as South Island dairy farmers with large-scale irrigation operations - would also be in for change.
"We'll be making changes there. We will be charging where there is commercial use of a water resource ... I'm sorry, those that use the water will be paying for the water," Mr Goff said.