Pachymerinus australis is a species of centipede in the Geophilidae family. It is endemic to Australia, and was first described in 1920 by American biologist Ralph Vary Chamberlin.
The original description of this species is based on a specimen measuring 45 mm in length with 71 pairs of legs.
The species occurs in New South Wales.
The centipedes are solitary terrestrial predators that inhabit plant litter, soil and rotting wood.