Australian authorities are investigating what could become the first confirmed case of H5N1 bird flu on the country's mainland after a dead migratory seabird tested positive for avian influenza in Western Australia.

The bird, a brown skua found in Cape Le Grand National Park, was discovered dead and subsequently tested positive for bird flu, officials said.

Further laboratory analysis is underway to determine the exact strain of the virus. Authorities expect confirmation results to be released on Friday, which will establish whether the case involves the highly pathogenic H5N1 strain.

Western Australia Agriculture Minister Jackie Jarvis said officials were treating the suspected case with the utmost seriousness and were prepared to launch a coordinated national response if the virus is confirmed.

Wildlife veterinarian and Associate Professor Wayne Boardman of the University of Adelaide warned that the virus could have significant consequences for Australia's native wildlife populations if it becomes established on the mainland.

Since 2021, the H5N1 strain has spread widely among wild birds across multiple continents, causing the deaths of millions of birds and other animals.

Australia has long been regarded as the only continent free from the deadly H5N1 strain. The virus was previously detected only on Heard Island, an Australian external territory in the southern Indian Ocean, in late 2025.

The latest case has heightened concerns among wildlife and biosecurity authorities as they await confirmation of whether the virus has reached mainland Australia for the first time.(ILKHA)