Fish and Game and the Environment Defence Society are taking on the Horizons Regional Council in court today in a bid to improve its regional plan, including rules around farming and conversions.
One Plan was developed by the council to manage the Manawatu-Whanganui region's quality of freshwater, air and land by monitoring discharges and run offs from farms and businesses.
However, Fish and Game and the Environment Defence Society are worried it has not been implemented properly, especially the resource consent applications for intensive farming and dairy conversions.
Today is the first day of the case in the Environment Court in Wellington.
Fish and Game's Wellington Regional Manager, Phil Teal is at court and says they are fighting for the plan to be improved.
"Nitrogen leaching is one of the key aspects that we thought the One Plan/Regional Plan would be dealing with.
"The way that the regional council has implemented it - we're not confident that the long term benefits they are expecting and the intent of the plan will come to fruition."
He said they are not expecting a radical change from farmers, but they do want a change.
"Over the next 20 years we're expecting a significant reduction in nitrogen leaching."
By going to court Fish and Game and the Environment Defence Society are hoping to clarify how the plan has been interpreted by Horizons Regional Council and how it has been implemented to date, said Mr Teal.
The court case is expected to last a week.