The Green Party is calling on the Government to take a zero-tolerance stance towards contaminants in milk products.
It comes after the discovery of the chemical Dicyandiamide, or DCD, in Fonterra milk - an issue which has been highlighted by media reports in China and the US.
"Our 100% pure marketing advantage is crucially important to our farmers, and we should be protecting it, not asking the rest of the world to expect less than 100%," Green Party agriculture spokesperson Steffan Browning said.
"The solution is less reliance on industrial dairy; if our land can't support it then we need to be looking at what we can produce while protecting our environment and providing clean food to our markets."
The Wall Street Journal reports that Fonterra knew traces of DCD were present in its milk, but chose not to tell investors ahead of the launch of a multi-million dollar fund last November.
The Journal said the company had not considered it "material" information. It also mentioned the 2008 melamine scare which threatened the multi-billion dollar milk export industry.
Prime Minister John Key said the DCD discovered in the milk posed no health threat to consumers.
"The risk is a marketing and perception risk rather than a health and food safety risk," he told TV ONE's Breakfast.
"DCD is a fertiliser that is put on land, cows effectively eat the grass and it shows up in very small traces, less than 100th of the amount that is legally allowed. There is no health safety risks you'd have to drink a swimming pool full of milk to have any impact."
He said officials in China and Taiwan will understand the low-level risk but the danger is if media reports link DCD to melamine, which Key said was an illegal substance that killed infants.
Fonterra Chief Executive Theo Spierings said all New Zealand milk products were safe to consume.
"We do have strong science and we have strong evidence providing assurances that all our products are safe," he said.
"We have only found minute traces of the DCD in our products and they are, to give you a comparison, a hundred times less than European standards as we speak."
The Government has been working closely with Fonterra to deal with the issue, the company says so far its sales have not been affected by the media coverage.