An eight-time winner on the U.S. Tour, Snedeker started the final day with a three-stroke lead and extended that to seven at the turn with four birdies during a brilliant front nine.
He stumbled on the 10th, but holed a monster putt for bogey to limit the damage and from there was unflappable heading back to the clubhouse as the chasing pack of Australian and New Zealand challengers fell away.
The win in the A$1.5 million ($1.14 million) co-sanctioned event, in his 61st attempt on the European Tour, was his first outside of the Americas and leaves the title in U.S. hands after Ryder Cup team mate Matt Kuchar's triumph last year.
New Zealand's Brad Shilton finished in a four-way tie for third with Australians Andrew Evans, Matthew Giles and Anthony Houston, 10 strokes adrift.
Three-times major winner Vijay Singh finished joint 21st at three-under for the tournament in his homeland.
(Reporting by Ian Ransom in Melbourne; Editing by Greg Stutchbury)
