George Robert Gray described the Norfolk parakeet in 1859 as Platycercus Cookii, from a specimen in William Bullock's museum, and recorded it as from New Zealand.

[6] In 1862, Gray described a specimen from Norfolk Island as Platycercus rayneri, collected by a Mr Rayner.

[7] In 1891, Italian ornithologist Tommaso Salvadori confirmed the two taxa as synonymous and coming from Norfolk Island.

However, the latter subspecies was not included in the genus-wide phylogenetic reconstruction using DNA sequences, and the lumping of the species should be considered tentative.

Factors contributing to its decline include habitat loss, particularly of large old trees with suitable hollows for breeding, killing of eggs and young by rats and cats, shooting by early settlers, and competition for nest sites by introduced crimson rosellas and common starlings.