Scientists are about to trial a new nitrate sensor that can detect river pollution as and when it happens.
Auckland University associate professor Ashton Partridge said work has been underway on the project for several years, with help from the Callaghan Innovation fund.
He said the instruments can record effluent or other nutrients going into the water and send the data back to a computer via satellite or wifi.
Mr Partridge said the sensor will go out into the waterways at the end of this week, and his team will build ten over the next few months.
He said five will go into Northland Rivers, and five into the Waikato.
Mr Partridge said water-quality monitoring is currently costly and labour-intensive and the nitrate sensors are potentially a game-changer.
He said the next step in the project is to find a way to neutralise the nitrates, and research is now underway on that as well.