Fish and Game says an Environment Court ruling on farming restrictions in the Manawatu-Whanganui regional plan will set a precedent for the rest of the country.
The court considered more than 20 appeals against the Horizons Regional Council's proposed One Plan.
Its ruling means that, to continue operating, all intensive farming and horticulture operations will have to have consents for nutrient management plans.
That includes irrigated sheep and beef and cropping farms, as well as dairy farms and market gardens
It's the first regional plan to tackle water pollution by setting limits on fertiliser and other farm nutrients going into catchments.
Fish and Game chief executive Bryce Johnson says the court has restored environmental protection measures originally proposed by the regional council that were watered down by the commissioners who heard submissions.
He says the One Plan, backed by the Court's ruling, is precedent setting for other regions preparing plans and sends a strong signal that agriculture has to be managed more tightly to minimise its environmental impact.
But farmers say the plan will impose unnecessary regulations and extra costs on them, threatening their viability .
Federated Farmers Ruapehu president Lyn Neeson says it's not just intensive farming that's been targetted.
She says new measures to protect biodiversity will also have a big impact on hill country farmers, such as imposing more regulations and costs in finding out what they can and can't regarding blocks of trees and scrub.
The Manawatu-Whanganui regional council will produce a final version of its One Plan for the Environment Court to sign off.