According to the Queensland Museum website they are commonly known as jewel bugs. This particular species is the Hibiscus Harlequin Bug (tectocoris diophthalmus).
Females lay clusters of eggs around twigs and guard them until they hatch. The nymphs are often a different colour to the adults. The Hibiscus Harlequin Bug is found in coastal dunes, rainforest, open forest and gardens in northern and eastern Australia, New Guinea and some Pacific islands.
Length about 15 mm. The body is rounded and convex. Its colour varies, from pale orange to heavily patterned with metallic green, blue and red.