The Ruamahanga River will be the first stop on a nationwide Green Party tour focusing on making rivers "swimmable".
The party has launched a campaign for better water quality, looking at 10 rivers around the country.
The first stop next month will be the Ruamahanga, where party leaders hope to meet with mana whenua and community groups to discuss the future of the river.
Green Party water spokeswoman, MP Catherine Delahunty, said the Ruamahanga had been selected as part of the campaign because of the twin challenges of dairy pollution and sewage.
"It's an example of some real challenges," Ms Delahunty said.
"It's a good place for us to start -- it's a beautiful river and it should be swimmable."
The proposed irrigation scheme was a "unique threat" which could also increase the load on the river, Ms Delahunty said.
"It was good to focus on this beautiful river and see what we could do to support its clean up."
Green Party co-leader Metiria Turei's father, Richard Turei, was from Papawai and had grown up swimming in the Ruamahanga, Ms Delahunty said.
"It's very important to her," she said.
Speaking at the party's annual conference, Green Party co-leader Metiria Turei said rivers needed to be clean enough to swim in. "Government subsidies for damaging irrigation projects -- like the Ruataniwha dam that will impact the Tukituki River -- shows the Government's refusal to protect water quality.
"Lots of work is being done by tangata whenua, communities, industries and farmers, but they can't do it on their own. We need strong regulation that requires our rivers be safe for swimming.
"Rivers can be clean enough to swim in, but only if the Government lifts its 'wadable' standards and demands they be swimmable instead."
The 10 rivers which form part of the campaign are the Wairua, Kaipatiki/Lucas Creek, Waikato, Tarawera, Tukituki, Waitara, Manawatu, Mataura, Waikirikiri/Selwyn and Ruamahanga.