Phocarctos hookeri has been threatened by commercial squid fisheries since the 1970s. Incidental catch within fishing nets is high compared to the small population size. There is a 2.4 per cent female mortality relating to incidental catches. There is also a high juvenile mortality caused by the presence of rabbit burrows.
Phocarctos hookeri inhabit the subantarctic islands of New Zealand, between latitudes 48 and 53 degrees South. The population distribution is centered on the Auckland Islands. It is believed that it never had a larger range.
The IUCN have urged the New Zealand Government to declare a Marine Mammal Sanctuary and take effective measures to protect the New Zealand Sea Lion and promote an increase in their population. The IUCN/SSC Seal Specialist Group suggest the following conservation measures: an examination of effects of incidental catch on age and reproductive status, a revision of fishing regulations to reduce incidental mortality, the management of rabbit populations and aeriel surveys and ground counts.
There are, at most, between 10,000 and 15,000 Phocarctos hookeri in existence.
Phocarctos hookeri is considered by the IUCN as "Vulnerable".