I think "hobo" is not just an Australian term. Here's an extract from Wikipedia:
A hobo is a migratory worker or homeless vagabond—especially one who is penniless. The term originated in the Western—probablyNorthwestern—United States around 1890.[1] Unlike "tramps"—who work only when they are forced to, and "bums"—who do not work at all, "hobos" are itinerant workers.[1][2]