Norfolk Island is a self governing territory of Australia (The only one). If an Australian citizen wants to travel there they must travel with a document of identity (which is designed specifically for Australians to visit Norfolk Island without the need for a passport) or with a passport Foreigners are required to have a multi entry Australian visa or they will not be permitted back into Australia. Australian citizens do not have right of residence there (more a result of Norfolk's tax haven status) without a permit Norfolk is not subject to duty tax either so plenty of shopping not much else but very pretty part of the world.