Four new species of terebellid polychaetes were found among unidentified or misidentified material deposited at the Australian Museum, Sydney while a study on the phylogenetic relationships among terebelliform polychaetes was being carried out. These new species are herein described and compared with the most similar congeners and, in cases of Amphitritides and Spinosphaera, comparative tables for all known species of these genera are provided. Amphitritides carawa sp. nov., is characterized by having 19–22 pairs of notopodia and nephridial papillae on segments 3 and 6–19, inserted anteriorly at base of notopodia and vertically aligned with them. Spinosphaera barega sp. nov., is characterized by having eyespots arranged in a circular patch on the lateral areas of the prostomium, 23 pairs of notopodia, characteristic “spinosphaera chaeta” present from segment 10–11 and nephridial papillae absent or not visible. Decathelepus wambira sp. nov., is distinguished from D. ocellatus, the only other known species of the genus, by lacking a tongue-like process originating from the distal part of the prostomium and by the morphology of notochaetae. Streblosoma bingarra sp. nov., is distinguished from other species of the genus by the presence of a large lower lip, arrangement of branchial filaments and the ventral surface on anterior body being tessellated and highly glandular.