The genus Haplostylus Kossmann was separated from the genus Gastrosaccus Norman to accept those species in which the endopod of the third pleopod of the male is uniarticulate. Bacescu (1973), Hatzakis (1977), Fenton (1990) and Green-wood et al. (1991) have discussed in detail the current status of the genus Haplostylus with respect to its closely allied genus Gastrosaccus. With the addition of the present species, the known Haplostylus fauna in the Australian waters consists of 14 species as follows: H. indicus Hansen, H. dakini Tattersall from New South Wales (Tattersall, 1940), H. pacificus Hansen from North East Great Barrier Reef (Bacescu, 1979), H. bengalensis Hansen, H. brisbanensis and H. queenslandensis from South East Queensland (Bacescu and Udrescu, 1982), H. robusta from South West Australia (Panampunnayii, 1989), from Broken Bay, New South Wales (Dakin and Colefax, 1940) and from Bass strait (Fenton, 1990), H. uderescu from Central Eastern Australia (Greenwood et al., 1991), H. australiensis from South East Queensland and New South Wales (Wooldridge et al., 1992), H. flagelliforma sp. nov., H. similis sp. nov., H. multispinosus sp. nov., H. uthupus sp. nov. and H. dispar sp. nov. Panampunnayii from South West Australia. The specimens described below were collected from the south-west coast of Australia from station slying between latitude 33 degrees 14'-35 degrees 16'S and longitude 114 degrees 28'-119 degrees 29'E. Samples were taken by a monofilament nylon net (mesh 335 mu m, mouth area 1 m sup(2) from the upper 50 m of the water column by oblique hauls. The samples were received at the Regional Centre of the National Institute of Oceanography, Cochin from CSIRO, Australia. All the type forms are deposited in the Reference Collection of the Indian Ocean Biological Centre-national Institute of Oceanography, Cochin, India