The Green Party will put a nitrate pollution levy on dairy farmers to pay for the clean-up of the country's rivers.
The party announced its "game-changing" plan for healthy rivers and sustainable dairying at an organic farm in the Wairarapa this morning.
Its levy is expected to raise $136.5 million in the first year, to be spent on sustainable farming projects, preventing pollution in waterways, and reducing risk for farmers wanting to transition to organic and environmentally-sustainable production.
A moratorium will also be placed on new dairy farm conversions, Crown Irrigation investments will be wound up, and the importing of palm kernel will be phased out.
Leader James Shaw said scientists and environmentalists told the Green Party that New Zealand must reduce the number of cows on farms to clean up the environment.