All options remain on the table against Russia, if reports an Australian prisoner of war has been executed are verified, the foreign minister says.
Australian officials are urgently trying to ascertain whether Melbourne teacher Oscar Jenkins has been killed by Russian forces in Ukraine after being captured while fighting for Ukraine.
The 32-year-old was captured and shown in social media videos visibly bruised and shaken while being interrogated and beaten by a Russian-speaking captor.
"We are making urgent inquiries following the reports of his death; these reports have not yet been verified," Foreign Minister Penny Wong told ABC radio on Wednesday.
"We hold great concerns for his welfare."
The Russian ambassador to Australia has been hauled in over the issue as Australia seeks more information.
Senator Wong said Russia was expected to comply with international humanitarian law.
"This includes humane treatment and the right to a fair trial, so that is their obligation," she said.
"We will look at the facts when they have been ascertained but I want to be clear, all options are on the table."
Australia has so far resisted expelling the Russian ambassador, with the federal government arguing it is better to keep channels of communication open.
"This has been a very difficult relationship for many years, including the downing of MH17 in 2014 as well as the illegal and immoral invasion of Ukraine," Senator Wong said.
"Australia has maintained diplomatic relations with Russia through that period under different governments.
"However, we will consider all options once we have ascertained the facts and once we can verify what has actually occurred."
But the federal opposition is demanding the expulsion of the Russian ambassador if the reports are true.
Senator Simon Birmingham said if Russia had undertaken an extrajudicial execution of a captured Australian citizen the Albanese government should respond in the strongest possible terms.
"Nothing less than the recalling of Australia's ambassador to Russia and expulsion of Russia's ambassador would be sufficient in such circumstances," he said.
"Three years ago the then Labor opposition urged Russian diplomatic expulsions, yet in government Labor have undertaken no such action," he said.
"If Russia has engaged in such an egregious and illegal action then it must now be a catalyst for action."
Kyiv has "great sympathy" for fighters like Mr Jenkins and sent its respects to his family, Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, told the ABC.
"Ukrainian Russia has a deep-seated hatred of foreigners like Mr Jenkins, people who have made the responsible choice to stand up for the rule of law and freedom by supporting Ukraine," he said, according to a translation.
"At the same time, we recognise Russia does not adhere to any conventions, including those regarding the treatment of prisoners of war."
In the social media video circulated in December, Mr Jenkins was shown speaking a mix of broken Russian and English.
"Live in Australia and Ukraine. I'm a teacher," he said.
The man asked Mr Jenkins in Russian how it was he came to be in Kramatorsk, a town 700km east of Kyiv in the Donbas region, near the Russian-Ukrainian frontline.
Mr Jenkins is the first Australian combatant reportedly captured by Russian forces in Ukraine and his death would mark the first for an Australian prisoner of war in more than 70 years.
Russia has said foreign citizens fighting for Ukraine will be prosecuted as mercenaries and face up to 15 years in jail, which would contravene international law.
With AAP.
