Funnily enough, people argue he had an Australian accent in the "Sonic the Hedgehog" OVA/movie from the '90s. Except... when you hear it, it's a Brooklyn accent. Not Australian at all.
Now, as for Sticks, there is the tiniest hints of an Australian accent in there, but it may possibly be the nasal delivery. It's not a common trait to the Australian accent any more, but an old stereotype of Australian voices is nasal delivery... although we use that more when mocking Americans.
Above all, though, Marine uses Australian slang... but the writers for her, at least in the comics, have literally no idea what the slang they make her use actually means. I've had a good chuckle over that recent Sonic Universe arc because of their poor grip of Australian slang.
Silverfanthing wrote: I'm Australian,and she doesn't sound Auzzie.And another thing.... JUNGLE BADGERS AREN'T AUSTRALIAN!
Nor are Raccoons... but Echidnas are.
As an Australian, I DO hear an Australian accent in there, but it's pretty buried. It's just that the pitch of that voice is going to drive me even more insane than I already am.