[5] After analysis using molecular genetic methods in 2000, the current consensus among researchers, which is accepted by the New Zealand Department of Conservation, is that Cyanoramphus malherbi is a distinct species.

Its body is primarily a bright blue-green, with azure blue primary covert and leading edge feathers on its wings.

[10] It has a distinctive (and diagnostic) orange frontal band on its yellow crown, but this is absent in juvenile birds, which have fully green heads.

[4][10][12] In the South Island, the parakeet is predominantly found only in Nothofagus/Fuscospora (beech) forest[4][10][13] with some reports from alpine and subalpine tussock and open matagouri shrubland.

[13] The Malherbe's parakeet typically feeds in the canopy of New Zealand beech trees, but will also forage in low vegetation and on the ground.

[10] They are typically observed feeding in flocks of mixed species, eating various seeds, beech flowers, buds and invertebrates.

[13] They have been observed feeding on herbs and ferns on the ground, including Pratia, Oreomyrrhis colensoi, Parahebe lyallii, Leptinella maniototo and Blechnum penna-marina.

[17] Malherbe's parakeets are monogamous and able to nest year round, but peak breeding is between December and April.

[4][10] During seeding events, and other periods where food is plentiful, they are able to produce secondary clutches, with some pairs reportedly breeding up to four times in succession.

[14] This behaviour has stopped due to low numbers and habitat modification, which also has implications for re-establishment of the species.

[20] The Hawdon River valley houses the largest population, with 70–200 individuals reported in 2013, but numbers are apparently decreasing.

[4][10] The original decline in population was most likely due to habitat destruction and fragmentation by human activity, hunting,[21] and predation from exotic species.

Introduced birds, mice, wasps, and rats are considerably reducing invertebrate numbers, which the parakeet relies on during winter and spring.

[17] Inbreeding depression and low genetic diversity may affect the viability of these small populations by reducing their capacity to adapt to threats and diseases.

[20] These pest management strategies have worked with other New Zealand bird species to reduce predation by introduced mammals.

[4][10][20] The other major conservation strategy is captive breeding programmes carried out at Peacock Springs by the Isaac Wildlife Trust, with individuals being released on predator-free islands.