The evacuation of Macquarie Island over bird flu concerns was "unnecessary" and could increase environmental risks, expeditioners told the government in a letter obtained by the ABC.
In late August, the federal environment department announced plans to temporarily remove all 24 expeditioners from the island, which sits about 1,500 kilometres south-east of Hobart.
It said this was necessary to avoid the "psychosocial" impacts of a potential outbreak of the H5 strain of bird flu, which has caused mass mortality events among wildlife elsewhere.
"We can't ignore the psychosocial risks of living near potentially large numbers of affected animals," the department's deputy secretary Sean Sullivan said at the time.
All of the expeditioners were evacuated in August, due to concerns they could suffer "psychosocial" damage from witnessing a prolonged bird flu outbreak. (AAD)
But days later, multiple expeditioners sent a letter to Mr Sullivan and leaders at the Australian Antarctic Division (AAD) questioning the rationale for the unprecedented withdrawal of staff.
"Whilst safeguarding personnel is of paramount importance, characterising the potential of witnessing wildlife mortality as an unmanageable psychological hazard overstates the risk and undervalues our rigorous preparation, training and resilience," they wrote.
The expeditioners, who underwent psychological and medical assessments before being deployed, arrived on the island in April and were expected to spend up to a year there.
In their letter, the researchers argued the decision undervalued their "rigorous preparation, training and resilience". (Supplied: AAD/Cris Ambrozie)
In the letter, the expeditioners said they were more than capable of dealing with the psychological toll of an outbreak, and had undertaken specific training as part of the department's official bird flu response plan.
"The harsh reality of [bird flu] was openly discussed and addressed during our summit week [in Hobart], and every individual who signed their contract did so with the full awareness that the risk of the virus arriving was high," they wrote.
The letter noted other countries had maintained a presence on sub-Antarctic islands impacted by bird flu, including Crozet, South Georgia and the Falklands.
"Evacuating a station that currently lacks confirmed cases of [bird flu] based on predictive distress is not only unnecessary, but it also fundamentally eclipses the purpose of maintaining a permanent sub-Antarctic presence.
"To understand, monitor and mitigate environmental threats at a time when an understanding of this panzootic is most needed."
The wildlife is in close proximity to people at Macquarie Island. (Supplied: AAD)
Fuel farm 'at risk' without expeditioners on island
The expeditioners also warned aging infrastructure on the island could pose an environmental hazard.
"The age and current condition of the station fuel farm presents an unacceptable risk to the environment without personnel on-site," they wrote.
"Should a critical infrastructure failure or a fuel leak occur, remote cameras provide no preventative capability and may fail to detect the incident entirely.
"Even if captured, a physical response team would take up to 12 weeks to arrive."
The expeditioners fear leaving the Macquarie Island fuel farm unmanned could result in major environmental damage. (Supplied: AAD/Gary Lynskey)
The letter concluded by urging the department to allow a smaller team of expeditioners to remain on site throughout summer, until their original departure date next year.
"This allows the AAD to maintain the station infrastructure, meet scientific stakeholder obligations and manage the local environmental response as we were trained and contracted to do."
A grey headed albatross on Macquarie Island shelters its chick from the rain (Australian Antarctic Division: Melanie Wells)
Department defends decision to remove staff
The expeditioners returned to Hobart last week after being picked up by the RSV Nuyina, Australia's primary polar icebreaker.
Samples collected on the island have since confirmed the presence of H5 bird flu in an elephant seal and a kelp gull.
In a statement, the department said its decision to temporarily withdraw expeditioners was based on a detailed risk assessment and workplace health and safety legislation.
"This was a difficult decision which the Department of Climate Change, Energy, the Environment and Water recognises was not supported by everyone," it said.
The department said while training was provided to expeditioners for responding to a "wide range of operational scenarios", the situation on Macquarie Island "was likely to create pressures that went far beyond the usual expectations."
"While the risk of personnel contracting H5 bird flu was low, the potential psychosocial impacts of a prolonged wildlife mortality event were assessed as major," it said.
"In addition, organising an unplanned retrieval voyage to Macquarie Island would have required substantial planning and had the potential to disrupt the Antarctic season."
The Department of Climate Change, Energy, the Environment and Water says cameras have been installed on the island to allow for remote monitoring. (Supplied: AAD/Pete Harmsen)
The department said a range of cameras had been installed on the island to allow for remote monitoring.
It also said the AAD was planning to remove the remaining fuel on Macquarie Island.
"This work ensures the ongoing stewardship of the station during the hibernation period."
It remains unclear when expeditioners will be able to return to Macquarie Island.