http://www.theage.com.au/victoria/merry-christmas-mr-fox-20140215-32sz8.html
There has been some talk that the accretion is not natural, however a quick look at Google shows that the high tide line is fairly even along the beach.
There was a similar case in QLD 2005, which resulted in a 5 year statutory stay on Surveys with ambulatory boundaries and a brand new shiny piece of legislation that was written by lawyers that don't understand survey that we now have to deal with.
Under the new QLD regulations (which I agree with, just the legislation to deal with it is a nightmare) this would not be allow to happen.
Seems like VIC might be in for a similar time. Good luck guys.
From the configuration shown, I'm guessing the beach would not be expanding but for the docks or jetty's that are shown. The prevailing current/wind is probably from left to right in that area and normally would erode in toward the tree line as claimed historically. In the U.S. the corp of engineers has published some studies on this. They used to allow permits to build jetty's by those who were experiencing erosion but found that it only caused the next property over to erode (long expanses which you don't have in the subject case because of the point to the right). There is also case law in the U.S. where this type of erosion or accretion has been deemed natural, even though due to artificial structures. Definitely some legislation needed that weighs public v. private interests. The trend in the U.S. is similar to down under; more public rights of access and use, less protection of "exclusive" private riparian interests.