Fonterra is standing firm in the face of another Chinese milk powder controversy, nearly two years after the Sanlu melamine scandal erupted.

Chinese dairy company Synutra International, which Fonterra supplies, is under investigation over allegations growth hormones in infant formula caused at least four children to develop prematurely.

Fonterra supplies whole milk powder and anhydrous milk fat to Synutra, but says the company also sources product from Europe.

New Zealand has strict legislative controls on Hormonal Growth Promotants, which can’t be given to milking cows, but also aren’t tested for on New Zealand milk products.

Chief executive Andrew Ferrier says he’s 100% positive Fonterra’s reputation will emerge unscathed.

Federated Farmers is standing by the dairy giant and its products.

Dairy chairman Lachlan McKenzie says he has complete confidence in the quality of Fonterra’s milk.

"If it was on purpose then it’s malicious contamination, but we stand 100% behind New Zealand products, it won’t have been contaminated from New Zealand milk.” 

Mr McKenzie says it wouldn’t make sense for cows here to be given the hormones in question.

“They’re not used in New Zealand, there’s no rational reason for using them in New Zealand – it stops the cow’s milking."

The New Zealand Food Safety Authority is working with Fonterra as the hunt for the source of the hormones continues.

FSA Principal Advisor for Chemicals Paul Dansted says it’s unlikely the hormones came from New Zealand.

“If there were anything coming out of China that was seriously linking this to New Zealand product we’d take it very seriously.

"At this stage it seems to be mostly conjecture by New Zealand media, it seems improbable so we’re just keeping a close eye on the situation in China.”