Bay of Plenty Regional Council is using recycled material to remove pollution from Lake Rotoehu near Rotorua.
The recycled rubbish comes in the form of 364,000 soft drink bottles that have been turned into a floating wetland about 100 metres offshore of Lake Rotoehu.
The council hopes the native plants growing on top of the structure will reduce levels of nitrogen in the lake.
The roots of the plants will reach down into the water and convert nitrate in the lake into nitrogen gas, which then escapes into the atmosphere.
Council spokesperson Andy Bruere says 300-400 kilograms of nitrogen will be taken out of the lake by this method.
Environment Minister Nick Smith says the newly created wetland is a step towards improving water quality in the lakes around Rotorua.
The wetland project is a joint effort between the Bay of Plenty Regional Council and the Te Arawa Lakes Trust.
The Regional Council has a resource consent to put similar structures on 11 of the lakes around Rotorua.