Despite widespread outbreaks overseas, Australia remained free from H5N1 bird flu until recently. This has been attributed to Australia’s geographic isolation, robust biosecurity and biogeographical barriers limiting migration of certain species. H5N1 was detected in Australia’s sub-Antarctic Heard Island in October 2025, and subsequently in McDonald Island. In June 2026, the virus was confirmed in sub-Antarctic migratory seabirds along Australia’s southern coastline in Western Australia and South Australia. Further cases have been confirmed since. This paper provides an update on the H5N1 situation in Australia.

While there are currently no detections in poultry or evidence of mass mortalities on Australia’s mainland, work is being undertaken to determine the extent of H5N1 and whether it has become established in mainland populations. There is a continuing risk of H5N1 arriving from the north via nomadic waterfowl and long-distance migratory birds, particularly during the spring migratory period. Native wildlife is likely to face severe consequences if H5N1 becomes established in Australia. As at June 2026, Australia remains free from H5N1 in poultry. However, potential impacts on the industry include production losses, farm closures, increased human health risk and trade restrictions. Response strategies may include surveillance, biosecurity and movement controls, and mass culling.

The paper provides an overview of Australian governments' response to the threat of H5N1.