While it's occasionally being seen a bit more, tipping is NOT expected in Australia. Wages are expected to cover the employees, and everything is included in your bill.
Indeed, in some places, tipping is forbidden - for example you might not be able to tip a security guard or dealer in a casino.
It's occasionally common to tell taxi drivers or waiters to "keep the change" if it's just a little bit left in change.
More often, cafes might have a tip jar on the counter by the cash register, and while it will usually get some cash going in there (people's left over change), once again it's not expected.
Short version: if you really want to tip for amazing service, go ahead, and it'll certainly be appreciated, but by no means is it expected.