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.
Asked what he thought farmers would make of both policies, Mr Goff said user pays was something he believed farmers understood.
Federated Farmers chief executive Conor English described Labour's ETS two-year-shift forward as a "tax grab".
He was hopeful that agriculture's biological emissions would still remain outside the scheme come 2015.
"It's just about raising revenue. The question [Labour] need to answer is - how will this tax improve the weather?"
Making water users pay for water was a complex issue which Labour was "oversimplifying," Mr English said, while further taxes would act as a heavy brake on the economy.
"Right now the number one thing we need to do is sell more exports ... we need to be putting a tailwind behind exporters, not setting a headwind for them."
The policy package also included plans to urgently review New Zealand's preparedness for maritime oil spills and ensure liability for clean-up of oil spills, target 90 per cent of electricity from renewable sources by 2025, extend the reserve around the Kermadec Islands and enlarge Aoraki/Mt Cook National Park.
In the wake of the Rena stranding, Mr Goff said deep-sea oil drilling such as that being explored off East Cape would be off the table under Labour.