MATE! ONLY COUNTRY THAT'S A CONTINENT MATE! MATE MATE CONTINENTAL MATEY MATE! TAKE THAT REST OF THE WORLD MATE!!
Sorry, had to get what passes for nationalism in Australia off my chest. It's an often spurious little statement in Australia mostly told to children or in patriotic speeches that "Australia is the only country that's also a continent :^)". Which isn't true at all given you're later taught that we're a part of Oceania including New Zealand and most Pacifican islands; and occasionally New Guinea in a sort of divorcée parents arrangement with Asia.
For what it's worth I've lived in Europe and the USA and I was always taught Australia was its own country-continent. The other Pacific islands were just kind of hanging out by themselves, not part of anything.