An ecology and zoology academic says future outbreaks of waterborne diseases could be prevented if New Zealand farmers moved livestock away from waterways.
The comments follow an outbreak of a campylobacter-related gastro bug sweeping through Havelock North.
Massey University's Dr Mike Joy was unable to confirm whether the outbreak was caused by livestock's faeces contaminating the water supply until more tests had been conducted. But he said there was a link between farming and waterborne illnesses.
He cited New York City's 1997 Watershed Agreement as a model for New Zealand to restructure its water supply system.
New York officials had had two choices to improve the quality of the city's drinking water - either spend $8 to $10 billion on a new water treatment system or move farms animals and other contaminants away from water ways, Joy said.
City leaders favoured the second option and now boast what The New York Times called "the champagne of drinking water".
Joy said the result had been a "win-win for everyone", with New Yorkers getting "fantastic clean water" and communities around waterways also becoming cleaner.
Water treatment facilities were of little use to preventing campylobacter outbreaks, because they were unable to filter out the pathogen, Joy said.
"Chlorine is the only thing that will get rid of it."
Earlier today, John Key told a post-cabinet press conference the Government would provide "any support" possible to the Hastings District Council to combat the outbreak of gastro illness. Key said he was "very concerned" about the outbreak and advised residents to follow instructions from health professionals.
While he acknowledged it was important to identify how the outbreak started, "the focus at the moment is on getting people well and on making sure others don't get sick".
He said contamination of the town's water systems was "unacceptable" and he would review the council's communication with the public about the water contamination, but was unable to confirm whether more could have been done to prevent the outbreak.
"We need to understand exactly how this material has got into the water system."