Ferrets were introduced to New Zealand from Europe in the 1880s, along with stoats and weasels, to control rabbits that were breeding out of control. By 1900, ferrets were well established in the wild and definitely played a role in the decline of native birds like the kiwi, weka and blue duck, and the extinction of kakapo on the mainland. Kakapo are now only found on mustelid-free islands.
In the 1980s, at least 17 ferret farms were established in Northland. When these closed down due to a downturn in the market, many ferrets escaped or were set free, contributing to the expansion of ferrets northwards into some of New Zealand's remaining prime kiwi habitat.
In addition to New Zealand's wild populations, ferrets are kept as domestic pets and farmed for export markets in Asia.