Dodgy Australian flags hanging from the ceiling of a Brisbane Coles store to celebrate Australia Day were bought from another retailer, the supermarket giant says.

In a statement issued on Monday, Coles said the banners, which included a reversed Southern Cross and an upside down Union Jack, were removed from the Toowong store as soon as the error was pointed out.

A Coles spokesman said all of the company's Australia Day merchandise on sale in stores, including flags, was correctly designed.