Family: Orchidaceae (Orchid family).
Native of Australia and NZ.
Common and widespread.
It is sometimes not easy to separate Slender Sun Orchid from Scented Sun Orchid. Slender Sun Orchid generally has paler flowers, fewer flowers, and smaller flowers, and they open less readily.
Photos 1: Castlemaine Botanic gardens. 2: Eureka Diggings. 3: Muckleford.