A national meeting of agriculture and environment ministers on Friday discussed Australia's response and preparedness after the country's bird flu tally reached 33.
The outbreak spans five states after the first case was confirmed in Victoria this week.
There are another 22 suspected cases including one in South Australia that caused alarm after a seagull was located at Robe in the state's southeast and sent to the CSIRO for confirmation.
Invasive Species Council chief executive Jack Gough said the seagull case was "a watershed moment".
"A seagull, one of the most common Australian seabirds, has now likely been infected and the government has declared that this deadly bird flu strain is here to stay," he said.
"We urge the Albanese government to get out ahead of the inevitable public outpouring of concern and grief by announcing a wildlife resilience fund of at least $200 million."
Agriculture Minister Julie Collins said leaders at the national meeting had vowed to do "everything we can" to help protect Australia's wildlife, agricultural industries and the national economy amid the outbreak.
The meeting on Friday 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.
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.Â
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.
Another greater crested tern at Portland in Victoria is also suspected to have H5 bird flu, after the state's first positive case was confirmed on Thursday in the same area.
Victoria's chief veterinary officer Graeme Cooke said the new suspect case highlighted the importance of early reporting of sick and dead wildlife.
"We have been preparing for the arrival of H5 bird flu, and we're now using those plans to support surveillance, testing and response activities across the state," Dr Cooke said.
"We ask Victorians to avoid contact with sick or dead wildlife, record what they see and report it."
Australian Chief Veterinary Officer Beth Cookson said all of the positive cases had been wild seabirds in 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.
"The risk to human health remains low."