Yeah, nah, it seems only Australians come out with that one. Australian sport commentators, who have a dialect all their own, are fond of constructions such as: "Yeah nah, at the end of the day it's all about going forward," "There are no heroes. The whole team are heroes," "The goys came out to ploy footy tonight [
o rly? not cricket, then? ], they all troyed their hardest, they all put in, but [the other team] were too good for them on the noyt," etc., etc.
Also this: You know you're a Tasmanian when you begin your answer to any question with "Yeah, nah," no matter whether you're answering in the affirmative, negative or otherwise: "You going to the pub tonight?", "Yeah, nah, I thought I'd check it out later on..."