The poorly known nabid genus Rhamphocoris Kirkaldy, 1901 is reviewed and the genus is redescribed. Four new species are described: R. linnavuorii sp. nov. and R. monteithi sp. nov. from Australia, R. sejunctus sp. nov. from Laos and Sarawak, and R. tenebrosus sp. nov. from Thailand. The male genitalia of R. linnavuorii and R. tenebrosus are illustrated and described. A key to species is given, which is based on species descriptions, photographs of R. borneensis (Schumacher, 1914), R. elegantulus (Schumacher, 1914), R. hasegawai (Ishihara, 1943) and R. reuteri (Bergroth, 1918), as well as original descriptions, and redescription of R. elegantulus. The description of R. linnavuorii and R. monteithi from Australia extends the distribution of the genus by >2500 km and is the first record of the genus east of Sulawesi. An overview of the Australian nabid fauna including two subfamilies, eight genera and 25 species, and a key to nabid genera found in Australian is given. A commentary on characters of the Nabidae is given, with reference to genital and external characters, as well a short discussion on the distribution of Rhamphocoris.