A species of squat lobster, Munidopsis kermadec new to science is described and illustrated from a hydrothermal vent area in Brothers Seamount, Kermadec Volcanic Arc, Southwest Pacific Ocean. It is distinguished from the allied Munidopsis lauensis, by the shape of rostrum, the erectness of eye spines, structure of the sixth abdominal segment and dactyl morphology of P2-4. This new record increases the number of species of Munidopsis reported from Southwest Pacific vent fields to five. A key is provided to distinguish the vent associated Munidopsis. New records of M. lauensis and M. sonne from Brothers Seamount are also reported here and this extends their distribution further south to the western Pacific. The habitat of the new species is briefly described. A note on the Munidopsis diversity in West Pacific vent fields is also provided.