Had a call from this number "Agent Walter" claiming to be from the ATO. His strong Indian accent made it difficult to understand what he wanted but the essence was that someone had made a complaint to the ATO about my tax affairs and they need to confirm my details.
Absolute scam. Just hang up on them. I suspect the Sydney number is a VOIP number

I received a call a few minutes ago from this number, sounds like the same Indian person as Amanda mentioned above, at 10:23am AEST on the 24/08/2015 and claimed he was from the ATO and I have been reported by someone to the ATO and I have a court case. I got immediately suspicious and told him that he was a scammer. He then tried to scare me that the police is on its way to arrest me. I told him that I call the ATO myself to clarify this and at that point he hung up.

Person called me about my criminal activities. Asked for my criminal lawyer which I provided but he hung up before I could give him a number to call.