The city centre the local government area and the metropolitian area are all called Melbourne are all in Victoria and are all in Australia Therefore it makes no sense to say that you can call one of them Melbourne and one of them Melbourne Victoria or even Melbourne Australia  All names can apply equally to all three geographical areas so you arent disambiguating at all  just causing more confusion  I think this does need to be discussed on WikipediaWikiProject Australian places as Melbourne isnt the only city with this naming conundrum