The flapjack octopods, genus Opisthoteuthis (Opisthoteuthidae) are globally distributed deep-sea finned octopods. The Opisthoteuthis fauna of many regions remains poorly understood, and members of this genus from Australian waters have been little studied. Herein, Australian Opisthoteuthis from southern and southeastern Australia, including Macquarie Island, were assessed using museum specimens, with comparisons made to other species traditionally allocated to this genus. Based on configuration of male enlarged suckers it is proposed that the genus be split into three genera, including the two new genera Insigniteuthis gen. nov. and Exsuperoteuthis gen. nov., and the genus Opisthoteuthis ‘sensu stricto’ be restricted to species sharing a similar pattern of male enlarged suckers with the type species O. agassizii. Redescriptions are provided for the two Opisthoteuthis previously known from Australian waters, O. pluto and E. persephone comb. nov. Two new species are described, O. kerberos sp. nov. from five specimens collected at 2 km depth off southeastern Australia, significantly deeper in bathymetric range than the other Australian taxa, and I. obscura sp. nov. from southeastern Australia and the Great Australian Bight. Description is also provided for a species from Macquarie Island, Australian Antarctic Territories, that may be comparable to the New Zealand O. chathamensis.