What I believe you were referring to when you are talking about the existence of an ‘Oceania region’ is an IP (or more obviously, /region au) that players who live in Oceania can connect to, to give them better latency on our Asia region. There is no standalone Oceania region.
The temporary Oceania region that existed a couple of years ago was created primarily to allow us to carry out infrastructure testing. At this time it is not feasible for us to add any more permanent regions.