People in rural Canterbury agree more needs to be done to stop nitrates leaching into drinking water, however there's mixed views on whether research is the answer.
A Danish study has found a connection between colorectal cancer and even very low nitrate levels.
Canterbury's medical officer of health Alistair Humphrey said it was time a similar study was done because the region had high rates of bowel cancer and growing problems with nitrates in the water.
Forest and Bird said nitrate pollution levels in Canterbury's drinking water were rising and the risk-maps the regional council relies on were out-of-date.
It has found an increasing number of private wells have nitrate levels above the safe standard for drinking water.
Mike Glover, who owns land near the Selwyn River, said nitrate levels in the well on his property had shot up in the past six years.
"It costs about $100 to get your water tested and we'll have to be doing that fairly regularly now... we haven't got a water filter yet, but we're looking at getting one and they're hundreds of dollars," Mr Glover said.
He said he was not sure if a study here would be beneficial in time.
"By all means start a study - but let's start reducing now - somehow... if you keep studying stuff while this nitrate keeps pouring in, you know, it's just going to get much much worse," he said.
Federated Farmers' water spokesperson Chris Allen said there was no need for further research.
"There's many sources of nitrate in our diets - there's nitrates that are in our vegetables, there's nitrates in the water, there's nitrates in preservatives," Mr Allen said.
"So just saying nitrates in Denmark equals nitrates, water equals colon cancer is a pretty loose connection," he said.
However, Otago University professor Michael Baker said a survey was long overdue.
"Our water is getting a lot more contaminated because of our absolute love-affair with nitrate fertilisers," Prof Baker said.
"The other thing that has happened is that we've got new knowledge about the danger level for human disease and it is much lower than the current threshold value. So I think we need to take that into account when we do further testing," he said.
He said the Danish study covered decades of data.
"The difficulty in New Zealand is that we may not have access to that exposure data - but I think as a first step - we really do need a comprehensive national survey," he said.
Sir Kerry Burke is a former Canterbury regional councillor and was chair for five years, until he was booted aside and commissioners brought in nine years ago.
He said he came under political pressure over the use of water.
"We're dealing with stuff that was done 10 or 20 years ago when farming interests dominated the regional council and seem to be granted water consents willy nilly," he said.
Sir Kerry said he supported Dr Humphrey's work and wanted more research to be done.
"You can't just keep on digging wells deeper and deeper into the ground to avoid the pollution - you've got to try stop it at the source - and that's what needs to be done," he said.
Mr Glover said modelling showed the amount of nitrates in his local catchment was expected to rise over the next 20 years.
He said authorities needed to act quickly to prevent it from becoming an even bigger problem for future generations.