Parents are being urged not to panic over dwindling supplies of a popular baby formula.

Some supermarkets and chemists have reported running out of Karicare Aptamil Gold, but doctors say there's no harm in switching brands.

Parents are rushing to stock up on the nation's biggest selling formula due to a shortage prompted by Chinese customers.

They have been bulk-buying the product to send home because of fears over the safety of infant products there.

Some frustrated new parents are being forced to search for the meal replacement at a number of major supermarkets and chemists, but they're not able to buy the formula in large quantities.

Some outlets have been rationing the product, allowing customers to buy as little as three tins at a time.

Leading paediatric dietitians say any of the brands sold here in Australia are safe to use, and there are a number of alternatives.

Sydney Children's Hospital dietitian Olwen Chell says the formulas are all very similar.

The company which supplies the product has confirmed there has been a surge in demand, but they say there is enough product here in Australia, and can arrange delivery to anyone who may be in need.