These flags mark the continent where an Australian person born overseas hails from. These flags are on the same scale of the Australian state flags. They conserve the original design to honor Australian heritage but with modified colours.
Please note these flags are not ethnic nor national flags. Rather they are geographical in nature. They simply represent the continent where an Australian was born.
For example imagine if an Irish-Australian family were working overseas at the Tokyo Embassy in Japan, and gave birth to a son in Tokyo. The son born of Australian parents in Japan would not be Japanese, ethnically nor by nationality. Japan is only his birth place, subsequently he would be entitled to fly the Yellow Aussie born in Asia Flag.
For a grand lot of Aussies born overseas, they can fly this flag as it has the UK and Ireland under its fold. Similar to the current national flag it differs with yellow stars and central white cross.
Each flag has a simplified canton with a unique pallet of colours, except for the two flags beyond the Old Wold and Americas.These flags are designed to evoke an Australian spirit yet show off the diverse voices that now compose modern Australia.
Terry Irwin is currently the best known American-Aussie at the moment. Although she was born up and over in the USA, she is now an Australian Citizen since 2009.