JohnThe tune sounds like one of the versions of The Wild Colonial Boy to me. I did a search on the net to see if I could find out what the original tune was but no luck so far. Infoseek found over a hundred refs to TWCB and I'm about a third of the way through checking them.
I also looked it up in John Meredith's Folksongs of Australia but it just mentions various people that Meredith collected the tune from.
Helen