A leading environmental group has warned Australians may soon face the distressing sight of lake shores lined with dead Black Swans, as the H5N1 bird flu outbreak spreads.

Invasive Species Council chief executive Jack Gough said people could expect to look “out at lakes across Australia where we’re used to seeing black swans and seeing none of them or large numbers of carcasses on the shore”.

“That is going to be a confronting sight for Australians,” he said.

Bird flu was first detected in migratory seabirds on a remote cape in Western Australia in June. Since then, it has spread to more than 200 cases across six states, including a little penguin that died on Phillip Island in Victoria.

A national risk report released earlier this month by the Department of Climate Change, Energy, the Environment and Water found both the little penguin and black swan faced a very high risk from bird flu in Australia.

The report also identified vulnerable or critically endangered seabirds such as the Christmas Island frigatebird and imperial shag among the species most at risk. Oceanic dolphins, including the pygmy killer whale and the common dolphin, were also assessed as being at high risk, along with magpie geese, robins, cockatoos, cormorants and swamphens.

The Kangaroo Island and King Island emus were judged to be both highly susceptible to bird flu and at high risk. The Australian southern cassowary, an endangered species closely related to emus, was rated as having moderate susceptibility but a high risk.

Mr Gough said the danger extended well beyond a handful of species and could cause severe declines in shorebird numbers, or even the “loss of some iconic species that so many people love”.

“The genetic isolation of Australia’s wildlife – which makes it so incredible, unique, so special – is also a high risk factor for having really big impacts from these novel diseases turning up,” Mr Gough said.

“So, it is not unlikely that the impact on Australia’s wildlife could be much worse than it has been overseas.

“That applies to some really iconic species, like black swans and cassowaries, emus, but even things like pelicans and ibises that people see quite a lot, where we could start to see mass die-offs and significant declines.”

He praised the government’s biosecurity response, but said a further $200m was needed for wildlife management, including weed control and feral pest management, to give native species a better chance of surviving.

“Look, we are not going to be able to stop bird flu,” he said.

“There is a wave of devastation that is building and is about to break across the entire continent. What we can do though is make sure that wildlife are able to recover after that first wave and are able to survive through subsequent waves.

“So, the next five years are absolutely critical for the survival of many of Australia’s wildlife … that means governments need to invest at scale in dealing with the other threats that we know they can do something about.”

The government has already spent more than $100m on bird flu preparedness, including surveillance and response measures.

Speaking in parliament earlier this week, Agriculture Minister Julie Collins said states and territories had identified species for a vaccination program.

“Over the weekend, the NSW government has announced priority species identified for potential vaccinations in NSW and they include little penguins and the regent honeyeaters,” she said.

“This builds, of course, on the announcements last week from the Western Australian government about its vaccination trial of threatened cockatoos at the Perth Zoo, including the Carnaby’s, the Baudin’s and the forest red-tailed black cockatoos.

“The Tasmanian government, of course, has indicated that it will prioritise the vaccination of the orange-bellied parrots.

“And I’m pleased to advise the House an update today, the Victorian government has now commenced the vaccinations of little penguins at Phillip Island and will then do St Kilda.”

Victoria has already begun vaccinating little penguins.

Ms Collins said “strong biosecurity remains our strongest line of defence”.

“The technical advice that our government has received is that as bird flu becomes more widespread in the wildlife, counting individual confirmed birds no longer gives us the clearest picture of where the disease is spreading,” she said.

“That’s why our reporting of the bird flu detections has now evolved from individual cases to focus on H5 events.”