Two plants are shown neither seemed to have any sign of a basal rosette (images 2 & 3) which suggests it is Centaurium tenuiflorum. However, the calyx is mostly around half the length of the corolla tube (images 4 & 5) which suggests it is Centaurium erythraea. The Flora of Victora indicates these two species form hybrids and I wonder if these are those.
I have always taken Centaurium erythraea to be pink (like most of the CNMsightings) and "Weeds of the South-East" says C. tenuiflorum is magenta/red. I have also seen a white-flowered plant but haven't really looked to see any other differences. IBIS shows colour variations in both species.