H5 bird flu has been confirmed in a native Australian seabird for the first time. A greater crested tern was found dead at Robe Marina, in South Australia's south east, reported to the national emergency animal disease hotline on Tuesday and collected the same day. It tested positive on Friday morning.

Every earlier Australian detection was in a migratory seabird that had come up from the sub-Antarctic. The tern is a resident species that does not make that journey. Authorities are treating it as an isolated case, and the working assumption is that the bird mixed with infected migratory seabirds on the coast or on offshore islands. Samples were tested at PIRSA's Glenside facility and at CSIRO's Australian Centre for Disease Preparedness.

The Department of Agriculture, Fisheries and Forestry's situation update, timestamped 9am on Sunday, lists 13 confirmed detections in wild birds nationally: seven in Western Australia, five in South Australia and one in New South Wales. All are in seabirds. The department says there is no evidence of infection in poultry or the wider agriculture industry, no mass mortality has been recorded anywhere in the country, and the risk to human health remains low.

The New South Wales case is the giant petrel found near Hawks Nest, now confirmed by CSIRO's disease preparedness centre. It is that state's first. New South Wales has stood up a state coordination centre at Orange and trained more than 500 additional staff for surveillance work.

The strain is H5N1 clade 2.3.4.4b, the lineage that has moved through wild birds and mammals on every other continent. Australia was the last to get it. The first case, a brown skua at Cape Le Grand National Park near Esperance, was notified to the World Organisation for Animal Health on 20 June. It did not arrive down the Asian flyways that biosecurity planning had watched for years. It came from the south.

Julie Collins, the Minister for Agriculture, Fisheries and Forestry, said the arrival was "of course" a concerning development but was "not unexpected and is another sign that our strong biosecurity system is working". She said there was no evidence of infection in the poultry or agricultural system.

Carol Booth, the policy director of the Invasive Species Council, reads it differently. She called the spread "extremely nerve-wracking". "We really need to be prepared for what could be a really devastating time ahead of us," she said. "Once it spreads into wildlife, there is probably no hope of containing it."

Skye Fruean, South Australia's chief veterinary officer, said the state had known this was coming, because the movement of wild birds in and out of South Australia cannot be controlled. She called the tern a new species but an isolated case, and credited the public for reporting it. "The fact that we found this in a single dead animal is really quite incredible," she said.

Surveillance has scaled up around it. In the week to Friday South Australia completed the largest aerial survey of its coastline in more than four decades, covering almost 5,000 kilometres of coast, islands and reefs by helicopter, plane, drone and field crew.

No commercial poultry flock has been affected anywhere in Australia and there is no impact on the supply of chicken meat or eggs. New South Wales has recommended heightened on-farm biosecurity and voluntary housing of free-range birds. The public is told not to touch sick or dead birds and to call the emergency animal disease hotline on 1800 675 888.