"Labelling a cow's milk product as breast milk is not acceptable.
"The product does not contain any human milk and does not come from a breast but an udder."
Stufkens said she was concerned mothers could mistake the product as breast milk.
However, Le Leche League New NZ spokeswoman, Lisa Manning, disagreed, saying she didn't think people were that "silly".
"They might momentarily pick it up and think 'oh what's this' but I don't think anyone would be silly enough to take it any further than that," Ms Manning told the Herald Online.
"I'm not worried, I don't think people are that daft."
Lewis Road spokeswoman Angela Weeks said she's confident there won't be any confusion as the milk is clearly marked as "cow's milk" and is stocked in the chiller alongside the regular range of milks.
"The last thing we want to do is mislead customers which is why the bottle clearly states twice on the front that it is cow's milk and twice on the back," Ms Weeks told the Herald Online.
"We gave the Breastfeeding Authority a heads up to let them know about the campaign should they receive any enquiries.
"We hope that the steps we have taken will ensure people see this product for what it is - a way that people can support a charity that is committed to finding a cure for breast cancer."
The price of the milk hasn't changed, each 1.5 litre bottle is around RRP$6.10 from supermarkets.
Lewis Road made headlines last year after a collaboration with Whittaker's Chocolate that saw them craft a chocolate milk which attracted a cult following, selling out around the country.
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- nzherald.co.nz