The Australasian Gannet generally feeds over continental shelves or inshore waters, seldom far from land. Its diet is comprised mainly of pelagic fish, especially pilchard, anchovies and jack mackerel, but also squid and garfish. Prey is caught mainly by plunge-diving, but it is also seen regularly attending trawlers. Breeding is highly seasonal (October to May), nesting on the ground in small but dense colonies. Adults tend to stay within the vicinity of the colony after breeding, with young birds dispersing (del Hoyo et al. 1992).

Breeding colonies are found off the coast of south-east Australia, Tasmania and New Zealand. One small colony is also found further north at Norfolk Island (to Australia). Winters in adjacent waters and up the east and west coasts of Australia as far north as the Tropic of Capricorn (del Hoyo et al. 1992).