Baby formula will be joining razors and cigarettes behind the counter at some NSW supermarkets to ensure Australian parents have enough to feed their infants.

It comes after reports that some baby formula brands, worth between $25-$35 for a 1 kilogram tin, were being bought in bulk from Australian supermarkets and on-sold to China for a profit of $100 per tin.

Over recent years Aussie mums have turned to social media and other platforms to express their frustration about not being able to get the brands their babies like, or need because they have dietary issues.

A series of fatal formula scares in China in recent years has made Chinese parents desperate to get their hands on safe products.

Coles says tins of baby formula will now be kept on shelves behind service desks or tagged with Electronic Article Surveillance lids in some stores, a supermarket spokeswoman said in a statement on Tuesday.

"Coles is committed to ensuring that our customers with a genuine need for infant formula have access to this product," the statement said.

Coles is taking preventative measures to stop the bulk-buying of baby formula. ( Reddit: puppy2010 )

Woolworths won't be following Coles, saying it is not in its policy to have baby formula behind their shelves or locked away.

"Baby formula remains available on the shelf for customers in Woolworths stores," a spokesman said.

"We're continuing to work with our suppliers to increase the supply of these essential family items."

Both Coles and Woolworths have a two-tin limit for customers.

At the Coles in Sydney's Five Dock, a sign has been erected in the formula aisle saying the removal was to provide "equal opportunity" to shoppers and to deter theft.

AAP