The 50g bar was sold in Coles, Woolworths, IGA, Kmart, Big W, convenience stores and some petrol stations.
It is unclear how many products are affected and how the problem was discovered.
It can also be found in the 'Cadbury Fundraiser Joyville Sweet Treat Box' and 'Cadbury Dairy Milk Variety Box' sold only at Costco, as well as some Cadbury showbags.
The chocolate has a best before date of 25/2/15 and 26/2/15.
Consumers should not eat the product and should return it to the place of purchase for a full refund.