By Jake Evans, ABC
Australia is urgently seeking to verify Russia's assurance that Oscar Jenkins, who travelled to fight for Ukraine, is alive and being held in Russian captivity.
Prime Minister Anthony Albanese said the government had received a report from Russia that Jenkins was alive and was demanding more information.
"I am reticent to confirm that is the case, but certainly that is the statement that has been made by Russian authorities to our department," Albanese told ABC Afternoon Briefing.
"We have received that information through the Department of Foreign Affairs and Trade, but we are seeking confirmation."
Jenkins was initially believed to have been killed by Russian forces after video emerged of his capture last month.
Russia's ambassador has advised that Jenkins was being held in the custody of Russia's armed forces on Russian territory, and his health condition was normal.
The government still holds serious concerns for Jenkins as a prisoner of war.
In a statement, Foreign Minister Penny Wong said Australia had made clear that Russia was obligated to treat Jenkins in accordance with international humanitarian law, including humane treatment, as he is a prisoner of war.
Wong said the government had also warned if Jenkins did not receive the protections he is entitled to, Australia's response would be "unequivocal".
It has called on Russia to release him.
Ukrainian authorities fear that Russia will seek maximum leverage from Australia for the release of Jenkins.
The government is working with the International Committee of the Red Cross to push for access to Jenkins in order to verify his welfare.
Hope after reports of death
Friends of the 32-year-old who had served alongside him told the ABC they feared he had been killed shortly after his capture last year.
While footage of the capture emerged late last month, Australian authorities were reportedly alerted to his "disappearance" weeks earlier.
The government warned at the time that if harm had come to Jenkins, Australia would retaliate with "the strongest action possible", including the possible expulsion of Russia's ambassador to Australia.
The Ukrainian ambassador to Australia, Vasyl Myroshnychenko, said the report that Jenkins is alive was "good news", but that the Russian government needed to provide "definitive video proof" of his wellbeing.
He also criticised Russia's delay in confirming Jenkins' status and called for him to be released.
Albanese said the government wanted to ensure any developments were first communicated to Jenkins' family before being shared publicly.
-ABC