During a recent review of Australian melitid amphipods (Lowry, Berents & Springthorpe, 2001), a number of problems and undescribed species were revealed. These problems and others uncovered during the course of this study are addressed here. The Melitidae, as currently conceived, is considered to contain at least five natural groups: the Ceradocopsis group; the Ceradocus group; the Eriopisa group; the Nuuana group and the Melita group. In the Ceradocus group Austromaera n.gen. is established for Maera mastersii Haswell, 1879a, that is redescribed based on syntype material and new collections from Port Jackson. Ceradocus circe n.sp. is described based on specimens from Tasmania, originally reported by Chilton (1921b) as C. rubromaculatus (Stimpson, 1856). Maera boecki Haswell, 1879 and Maera hamigera Haswell, 1879 (sensu stricto), both originally described from Port Jackson, are redescribed and these species as well as Maera octodens Sivaprakasam, 1968 are transferred to the genus Linguimaera Pirlot, 1934, recently re-established by Krapp-Schickel (2003). Linguimaera schickelae n.sp. is described from the Sydney area. Maera griffini Berents, 1983, is tentatively placed in the genus Maeropsis Chevreux, 1919. Mallacoota subcarinata is redescribed based on syntypes and new collections and four new Australian species (M. chandaniae n.sp., M. euroka n.sp., M. kameruka n.sp. and M. malua n.sp.) are described, two of which have previously been mis-identified as M. subcarinata. Mallacoota nananui Myers, 1985, is reported from Australia for the first time. Miramaera thetis n.gen., n.sp. is established for the specimens mis-identified by Stebbing, 1910a as Maera inaequipes. We describe a new species of Parelasmopus, P. sowpigensis n.sp., from Port Jackson, New South Wales. Quadrivisio sarina n.sp. is described from near McKay, Queensland, the first record of Quadrivisio Stebbing, 1907 in Australian waters. In the Eriopisa group Victoriopisa australiensis (Chilton, 1923) is redescribed and illustrated. A second species, Victoriopisa marina n.sp., is described from estuarine and marine habitats in New South Wales and Victoria. In the Melita group Dulichiella australis (Haswell, 1879a) is redescribed based on syntype material and D. pacifica n.sp. is described based on collections from the Great Barrier Reef, the southwestern Pacific Ocean and the South China Sea. Melita ophiocola n.sp. is described from Port Jackson, living in association with the brittlestar Ophionereis schayeri.