A new deep sea balanomorph,Tetrachaelasma tasmanicumsp. nov., is described. This new record is based on numerous disarticulated plates, from dredge samples around deep‐sea seamounts on the South Tasman Rise. This is the deepest known occurrence of the Balanomorpha, and the first record ofTetrachaelasmafrom the Pacific realm. An overview of the biogeography, including aspects of the palaeontology of deep sea balano‐morphs is provided. A map showing station localities and a list of deep sea cirripedes recovered from the South and East Tasman Rise during the 1995Rig Seismiccruise, are included.