Latoudis v Casey is the typically-cited case for the awarding of costs to a successful defendant. There are however a number of passages that highlight the misconceived nature that costs follow the event in criminal proceedings (especially when a prosecutor seeks costs after a finding of guilt).
At  of the judgment of Mason CJ (who agreed that costs in that case should be awarded to the successful defendant):
I am not persuaded that there is a complete analogy between the discretion to award costs in summary proceedings and the power to award costs in civil proceedings. For that reason I would not be prepared to accept that in summary proceedings there should be a general rule that costs follow the event. As I have noted, the making of separate provision in s.97(a) and (b) is not without significance. The differences between criminal and civil proceedings are substantial, not least of them being the absence of pleadings, the different onus of proof, the defendant’s inability in criminal proceedings to enter into a compromise and the possibility that the charge, if proved, may affect the defendant’s livelihood and reputation.
At  of the judgment of Dawson J (who dissented):
For all of these reasons, a successful defendant in summary proceedings for an offence can, in my view, have no expectation as a general rule, unlike a successful party in civil proceedings, that costs will be awarded in his favour.