A freshwater scientist says people are being deliberately misled about the damage of agricultural intensification.
Researchers at the New Zealand Freshwater Sciences Society annual conference in Dunedin say New Zealand is approaching a tipping point where expensive long term effort will be needed to return lakes and rivers to an acceptable state.
One of the speakers, Dr Mike Joy of Massey University, says industry bodies with vested interests in agricultural intensification are intentionally suggesting scientists aren't sure how much damage it is causing.
He compared their actions to tobacco companies suggesting scientists don't know if cigarettes damage people's health.
Dr Joy says so-called best practice farming can't do enough to stop freshwater degradation and the only real solution is to cut back on plans to intensify agriculture.
He says freshwater is an economic issue rather than an environmental one because New Zealand trades on its clean, green image.