Menzies was, according to one account, the specially-built interior capital of Australia, constructed to open up the country's desert areas. It was proximate to Station Orion, a radio telescope facility the Third Doctor once attempted to sabotage to prevent unwanted alien invasions. All of its buildings were new at the time the Doctor visited, since the entire city had only recently been built. The city also had an international airport by which the Doctor arrived, despite having by then regained use of his TARDIS. (COMIC: Is Anyone There?)
Behind the scenes
Menzies is wholly fictional. It seems to have some of the characteristics of Canberra, the real-life specially-built capital of Australia which also exists in the Doctor Who universe. The name likely derives from Robert Menzies, the long-serving Australian Prime Minister who was the fierce political advocate of Canberra.