actually.. in the first movie, its meant to be Australian. Trevor Goddard passed himself off as an Aussie around the time of the MK Movie and JAG.. it was only after his death did it get revealed that was something he did to land more roles.
I agree, it does sound more British.. but i'm guessing too, you haven't heard the real aussie accent.. the ones you hear overseas is different to the ones you hear in Oz.