A new monotypic Australian genus in the orb-weaving spider family Araneidae Clerck, 1757 is described, Venomiusgen. nov., with V. tomhardyisp. nov. as type species. Somatically, Venomiusgen. nov. is similar to the typical leaf-curling orb-weaving spiders, such as Phonognatha Simon, 1894 or Leviana Framenau & Kuntner, 2022, due to a similar elongate cylindrical abdomen and colouration; however, the genital morphology of the new genus is very different. Most unusual are the presence of two strong macrosetae on the male pedipalp tibia. Male pedipalp sclerites are complex, with diagnostic characters including the tibial macrosetae and a keeled median and a rounded basal process on the stipes. The epigyne of females is wholly covered by the scape that has a short median process. Venomius tomhardyigen. nov. et sp. nov. has been collected in southern Australia, from Tasmania to Western Australia, where it builds a circular, vertical orb-web. Spiders often hide in silk-lined hollows in branches of trees when disturbed during the day.