Greenpeace is bringing cardboard cutout cows onto Parliament's forecourt on Wednesday as it launches a new report linking intensive livestock farming with the safety of New Zealand's drinking water.
Some of the country's top doctors are getting behind the report, which warns that with the way things are going, there'll be a repeat of Havelock North's water contamination crisis.
Greenpeace is recommending putting a stop to the expansion and intensification of dairying, decreasing the number of cows and withdrawing public funding from irrigation schemes.
"Not only is intensive livestock farming endangering the health of our rivers, but the latest science says it may be putting our health at risk," Greenpeace campaigner Amanda Larsson says.
The report says contaminated water causes between 18,000 and 34,000 cases of gastrointestinal illness in New Zealand each year.
Public Health Association chief executive Warren Lindberg said in his foreword to the report: "It's no longer enough just to monitor the state of our water... the public health, environmental, tourism and industry sectors must start working together to stop the pollution in the first place.
"Where there is clear evidence of potential risk to human health, the Government has a responsibility to take the precautionary approach," Mr Larsson said.
"But right now, it's doing the opposite."