It is part of the "island thrush" complex that has been split into 17 species based on a molecular phylogenetic study published in 2023.

The two subspecies of the Tasman Sea island thrush became extinct in historical times.

[3] The Tasman Sea island thrush, under the name "island thrush", formerly included around 50 subspecies and had a range that extended from the Philippines through the Greater Sundas, Wallacea, and New Guinea to Polynesia.

The island thrush complex was split into 17 separate species based on morphological differences and a molecular phylogenetic study published in 2023.

T. p. poliocephalus was relatively common as recently as 1941, but by 1975 it had become extinct, due to introduced black rats, habitat loss and hybridization following colonisation by the closely related common blackbird.