While the Australian government is conducting pilot studies in non-poultry birds, New Zealand has already begun vaccinating some of its rarest birds after completing a world-first research trial last year.
About 300 breeding birds were targeted from five species: kakapo, takahe, black stilt, orange-fronted parakeet and shore plover.
But questions have been raised over whether a similar approach would be viable with Australian birds and other animals as the deadly strain's national toll soars past 100.
New Zealand used a different vaccine to the one that features in Australian trials.
Safety and efficacy data is still being gathered, and there are concerns about the logistics and practical application of such a program.
Two doses of any vaccine would need to be administered, with a period of time separating them, experts say.
The task of vaccinating wild animals would be especially challenging, University of Adelaide immunologist Mohammed Alsharifi told AAP.
"If we're talking about vaccinating wild birds, I think that's a big task," Associate Professor Alsharifi said.
"As the virus mutates and changes the nature of the surface structure, any existing vaccines may not be effective - it's a similar situation to human vaccination."
But Associate Professor Wayne Boardman, also from the University of Adelaide, said all options should remain on the table.
He said smaller colonies of Australian sea lions could be targeted for vaccination using innovative techniques including dart rifles or syringes mounted on long poles.
"Necessity is sometimes the mother of invention," he said.
There are fears for Australia's seals after a pup with bird flu symptoms died in Victoria.
It is potentially the first seal to be infected with the deadly H5 virus on the Australian mainland.
But in relation to Australian birds, Assoc Prof Boardman said the situation was much more difficult.
He pointed out that New Zealand birds like the kakapo and takahe were flightless "which helps".
He said New Zealand birds were all heavily managed, with many or the majority of their tiny populations monitored by tracking devices.
"In the Australian context, you'd be needing to think about which are the most important bird species that we need to consider vaccinating," he said.
The federal government has just released a susceptibility index, which scales the risk of H5 across native birds and mammals.
"If we don't do it, and they disappear because we didn't try, that would be an absolute tragedy," Assoc Prof Boardman said.
"We've got to think really hard about how we're going to do this.
"If we can vaccinate a proportion of the population, that's going to be better than nothing."
David Paton, an ecologist and ornithologist, said it was not a practical solution and called for other proactive approaches in an attempt to contain the virus.
He said birds should have been covered and removed as soon as they began appearing dead and sick along Australia's coastline.
"We should have had a much greater response base in terms of trying to minimise these contact points."
There have been 123 confirmed or presumed positive detections of H5 bird flu in Australia.
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