The only thing I could find online regarding this was this stackexchange with the accepted answer claiming that there is no legislation, only a ruling from the Australian Classification Board against some media that they said “depicted [young persons] on the bordeline of 18 years old.” I.e. it was a discretionary ruling by a statutory regulator that thought someone looked a bit too much like a child.
There are some more links on that stackexchange but some are dead and I only skimmed a couple of them so I encourage people to read through themsleves since I was too lazy to sort the situation out for myself; I only found enough to satisfy my curiosity and thought I should leave this comment to add context to a bizarre claim (not blaiming prev commenter, my memory is horrible too and I also found some news articles that were definitely depicting the situation the way they remembered)
The only thing I could find online regarding this was this stackexchange with the accepted answer claiming that there is no legislation, only a ruling from the Australian Classification Board against some media that they said “depicted [young persons] on the bordeline of 18 years old.” I.e. it was a discretionary ruling by a statutory regulator that thought someone looked a bit too much like a child.
There are some more links on that stackexchange but some are dead and I only skimmed a couple of them so I encourage people to read through themsleves since I was too lazy to sort the situation out for myself; I only found enough to satisfy my curiosity and thought I should leave this comment to add context to a bizarre claim (not blaiming prev commenter, my memory is horrible too and I also found some news articles that were definitely depicting the situation the way they remembered)