Farming representatives have argued that many producers operate within existing regulations and say agriculture is being unfairly singled out for broader environmental pressures.
A National Farmers’ Union (NFU) Cymru spokesperson said: “Welsh farmers produce food to some of the world’s highest standards and the industry is one of the most highly regulated sectors in the country.
“NFU Cymru is not in a position to comment on reports of legal action related to other groups or bodies.”
Sarah James, from the Country Land and Business Association Cymru (CLA), described the legal challenge as a “red herring” which risked creating “more of a gap between the industry and environmental groups and the communities that live around the rivers”.
She said if the focus remained on farmers alone and the nutrient management that those industries produce, “we are never going to fix the bigger problem of water quality”.
“There are a lot of other issues that come into the mix, when you look at the holistic view of a catchment like the Wye. It’s highly populated, everyone living in that catchment contributes to the nutrients in that catchment. Food production is only part of that story,” she said.
A Natural Resources Wales spokesperson said it was aware River Action had started proceedings for judicial review and was “awaiting the sealed documents”.
“As the legal process is now formally under way, we will not be providing any further comment at this time,” they added.