During voyages in 2017 off southern and southeastern Australia, the Australian Research Vessel Investigator deployed a series of demersal beam trawls to depths of around 5000 metres. Nineteen specimens of the rarely caught aphyonid-clade of the ophidiiform family Bythitidae, representing five species, were caught. Four of these are new to Australian waters: Barathronus pacificus Nielsen and Eagle, 1974 known from the northeastern and southwestern Pacific Ocean, Paraphyonus bolini (Nielsen, 1974) known from the western Indian and western Pacific Oceans, Paraphyonus rassi (Nielsen, 1975) known from the Atlantic Ocean and Sciadonus pedicellaris Garman, 1899, known from the northeastern Atlantic and northeastern and southwestern Pacific Oceans. Also included are Aphyonus gelatinosus Günther, 1878 known from all oceans including ten specimens from Australian waters, Barathronus maculatus Shcherbachev, 1976 known from South Africa to the westernmost Pacific including 13 specimens from Australian waters, Sciadonus longiventralis Nielsen, 2018 known from the holotype collected off New South Wales and finally Barathronus algrahami n. sp. known from the holotype caught off South Australia and four paratypes from off Taiwan and northern Philippines. Close examination of specimens collected during recent voyages combined with recent and ongoing studies by the first author and DNA COI barcoding analysis enabled an assessment of the aphyonid-clade species hitherto recorded from Australian waters. An identification key to the eight aphyonid clade species known from Australian waters is provided.