To my mind there is absolutely no compulsion to tip in Australia in the sense that there is in the US and some other places. You will not be beaten up if you don't. I once had an American waiter block the door when I left a 15% tip which was apparently not enough. I was an innocent callow youth.

If you do not tip in Australia despite the pressures (eg peer pressure, "I've always done it", the space on the credit card authorisation) you will still be able to walk tall. When visiting Sydney I regularly eat once a visit at the same restaurant in Crown Street. I am always warmly greeted and receive the same high standard of service despite never tipping. I guess its possible they may curse me behind my back but I don't think so.