Promising "rivers clean enough to swim in again", the Green Party says their latest environmental policy will focus on the quality of our water.

Dr Russel Norman Source: Breakfast

The policy was unveiled next to the Waikato river which was churned full of muddy water as a result of heavy rain.

The party says its three point policy - to be rolled out over the course of their election campaign - would see protection plans put in place for rivers, water quality improved and the construction of any new dams stopped.

But Irrigation New Zealand (IRZ) does not agree that dams and irrigation destroy rivers or add to pollution if they are designed and constructed properly.

"The reality is that New Zealand needs large scale water storage. This is essential for town and city drinking water supplies, as well as to produce fresh food," says Andrew Curtis, chief executive of INZ.

"Without water storage we would have to explore other expensive options to cope with future population growth. These might include implementing intense food price hikes; importing foreign fresh produce and building desalination plants.

"The reality is that it is unrealistic and prohibitively expensive to have swimmable rivers everywhere - particularly in towns and cities where water quality is by far the worst," Mr Curtis said.

Green Party co-leader Russel Norman says they have a vision for New Zealand where families can head down to their local swimming hole or beach and jump right in the water without worrying about getting sick.

"We're determined to make every single river in New Zealand clean enough to swim in again, it can be done," he said.