Merelina waitangiensis is a species of sea snail, a marine gastropod mollusc in the family Lironobidae. It is endemic to the waters surrounding the Chatham Islands of New Zealand.
In the original description, Powell described the species as follows:
The shells of the species measure in height and in diameter. It is the largest known species of Merelina found in New Zealand, identifiable by its 4-5 spirals on spire whorls, by having wider than high clathrate interspaces, and due to its uniformly buff colour.
The species was first described by A. W. B. Powell in 1933. The holotype was collected by Powell himself in February 1933, from shell sand at Waitangi in the Chatham Islands, and is held by the Auckland War Memorial Museum.
M. waitangiensis is endemic to New Zealand, found in the waters of the Chatham Islands. As of 2026, only two specimens have been recorded, the holotype and a specimen collected by dredging off the coast of Waitangi in 1995, at a depth of .