Powelliphanta was originally described by A. C. O'Connor in 1945 as a subgenus of the kauri snails, Paryphanta. They were named "in recognition of the great service rendered to the study of the family by Mr A. W. B. Powell", and from their similarity to Paryphanta. In November 2003 a subspecies, thought to be extinct, was rediscovered alive on the West Coast; it had last been documented on the basis of shell fragments in 1934.