Interesting site where you can input crash location and see where and when debris is most likely to wash up. It obviously depends exactly which position you nominate, but the densest flow of material is generally towards south and then SE coast of Australia (relatively densely populated).
Worth noting though that, from the example crash location you linked to, whatever type of plastic it is that they are modelling takes around a year to reach significant portions of the Australian coast.
So, given all the uncertainties, we are still relatively early in that process.