This taxon is Not Recognised as a species by BirdLife International.
Hemiphaga novaeseelandiae and H. chathamensis (del Hoyo and Collar 2014) were previously lumped as H. novaeseelandiae following Sibley and Monroe (1990, 1993).
BirdLife International (2016) Species factsheet: Hemiphaga novaeseelandiae. Downloaded from http://www.birdlife.org on 06/12/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/12/2016.