A suspected case of bird flu in a seagull had authorities on high alert as national leaders met on Friday to discuss Australia's response to the virus which now spans five states.
An initial positive test on the seagull found at Robe in South Australia's southeast has been sent to the CSIRO for confirmation.
The country's bird flu tally stands at 33, all found in wild seabirds.
Burnet Institute chief health officer Suman Majumdar said a confirmed case in a seagull would be significant.
"Gulls move between beaches, wetlands, farmland and urban areas, which could carry the virus into a much wider range of wildlife, poultry and environments," he told AAP.
Associate Professor Majumdar said overseas experience suggested Australia should expect further spread along coastlines, mass mortality events in seabird colonies and marine mammals, and rising detections in the weeks ahead.
"What we are seeing now is the early part of that curve," he said.
A national meeting of agriculture and environment ministers on Friday discussed Australia's response and preparedness.
Agriculture Minister Julie Collins said they had vowed to do "everything we can" to help protect Australia's wildlife, agricultural industries and the national economy amid the outbreak.
The meeting was briefed by experts on this week's decision to enact the H5 National Management Agreement.
The call was based on the advice of experts that the H5 bird flu in wildlife in Australia was not technically feasible to eradicate, Ms Collins said.
She did not directly address repeated questions about the potential risks if a case was confirmed in a seagull.
"What we do know is we have that local transmission in the greater crested terns in South Australia," she said.
Four new cases of the strain - all in greater crested terns - have also been confirmed on SA's Kangaroo Island, including one near a key breeding site for the endangered Australian sea lion.
Three are at D'Estrees Bay while the other is at Seal Bay, a sea lion breeding site on the island's southern coastline.
There are about 500 sea lions at the colony and the species' overall population numbers about 12,000.
"Beyond the Australian sea lion, we're concerned for other marine mammals such as fur seals; for seabirds that breed in large colonies, like penguins; and for scavengers that may feed on infected carcasses," Assoc Prof Majumdar said.
"We're especially worried for species that are endangered or found only in Australia."
Australian Chief Veterinary Officer Beth Cookson confirmed positive cases to date had been in wild seabirds at coastal locations.
"There remains no evidence of any mass mortality events and there are no detections in poultry or in our agricultural production system," she said.
But Assoc Prof Majumdar said incursions into poultry were likely despite best efforts.
"Overseas, this virus has hit poultry hard once it reaches them, which is why farm biosecurity is now so important," he said.
"Surveillance is the foundation - it tells us where the virus is and warns those most at risk.
"But it's not the only tool: carcasses can be removed, spread can be slowed, and farms protected."
The federal government had invested $113 million to prepare for the arrival of the flu in Australia, and released a further $24 million to states and territories in July.
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