Poirieria zelandica, common name the spiny murex, is a species of a large predatory sea snail with an operculum. It is a marine gastropod mollusc in the family Muricidae, the rock snails or murex snails.
Shells of Poirieria zelandica can reach a size of . These shells are roughly fusiforms, with long, straight spines. The aperture is ovate and large. The outer lip is thin.
This species can be found in Tasmania and New Zealand.