The adults of Trichosurolaelaps dixous Domrow, 1972 are redescribed from a population of Trichosurus cunninghami Lindenmayer, Dubach et Viggers, 2002 in south-eastern Australia. The nymphal stages are described for the first time. Morphologically, T. dixous is similar to Trichosurolaelaps crassipes Womersley, 1956. Morphological differences between the pre-female deutonymphs and adult females of the two mite species are the presence of a single large ventral spur on tibia I of T. dixous. Males of T. dixous could not be distinguished from T. crassipes morphologically and the idiosomal length of male T. dixous was variable (475-683 μm). Protonymphs of the two mite species differed only in size, with that of T. dixous being larger. Although T. crassipes was prevalent in a sympatric population of Trichosurus vulpecula and has been reported from other populations of T. cunninghami in southern Australia, it was never recovered from the population of T. cunninghami studied.