I think it is a "Ragged Robin" - Lychnis flos-cuculi, a herbaceous perennial plant in the family Caryophyllaceae.
It is certainly similar to this:
and it does get the same 'seed pods' like those in the Ragged Robin image.
While it is/was native to Britain, growing wild like my variety, intensive farming has all but eradicated it from most areas. It was probably introduced to Australia from Britain, probably as a cultivar at some time and its gone "feral" in Australian conditions.
This is how it (used) to bloom in Britain and, as such, is again similar to the way we found it blooming.: