The sign underneath the Bellamy's Organic baby formula shelf at the Cincotta Discount Chemist in Marrickville clearly states that there is a limit of two containers per customer, a ration strictly enforced due to the Australia-wide shortage of the product.

Retail operations manager of the inner west store Nerissa Burns said the product was almost impossible to secure and sold out almost immediately when it was in stock.

The chemist had supplies of Bellamy's Organic step 1 formula for infants on Monday but had run out of step 2 for babies aged aged over 6 months and step 3 for toddlers.

"We have to limit our sales to two cans per customer because so much stock has been sold to the Asian market," Ms Burns said.

"It is quite hard to get stock, especially of the step 3 formula. We would normally get about half a dozen enquiries each day but we have to be honest with our customers. If there is no stock, there is no stock. What can you do?"

Ms Burns said consumers needed greater awareness about formula, saying there are equivalent products in good supply.

"There are other brands which are just as good and are always in stock," she said.

At the Chemist Warehouse in Campsie, Bellamy's Organic was nowhere to be seen with a sales assistant saying she had also been fielding requests from anxious parents.

"It's very popular but no one has it," she said.

"We get quite a few requests each day. We have been out of stock for a while and when people ask us when it's going to be back in stock we can't answer. Some customers get very upset about it but there's really nothing we can do."

Further down Campsie's main shopping strip, a bulk shipping business was doing a busy trade packaging Bellamy's Organic for export to China.

The owner, who declined to be named, said he had seen the in-demand step 3 formula selling for $30, almost $10 more than it sells for on the Bellamy's Organic website.

He did not blame China's retail bonanza, Single's Day, for the shortage, blaming Bellamy's for the lack of supply.

"They (Bellamy's) would solve this problem if they sold more domestically," he said.

"Singles Day is only one day of the year. It doesn't explain the shortage."