Growing on dried out muds beside lagoon where water levels are receding.
Keyed out to Lobelia pratioides in Plant Net (PN), and in FloraVic (FV) and generally fits description given: noting that pedicels are described as having spreading hairs (PN) but as minutely pubescent (FV). Lobelia pratioides is essentially a species of Victoria (records in ALA) with occasional records in NSW and Tas.
Hoping someone can solve this !
I don't think this is Isotoma fluviatilis. The corolla is split to the base (a key characteristic for Lobelia, acc to PlantNet, and FloraVic ). Isotoma fluviatilis is a prostrate mat-forming species, whereas this is erect.