Foreign Minister Penny Wong announced on Sunday that Australia is backing Ukraine's claims of genocide against Russia in the International Court of Justice.
The government has also placed sanctions and travel bans on an additional 28 senior Russian officials and separatists following "sham" referendums held in four Ukrainian regions.
Senator Wong said the expulsion of Russian ambassador Alexey Pavlovsky was "under consideration" after Vladimir Putin threatened to use nuclear weapons.
Dr Pavlovsky told the Nine Newspapers any diplomatic expulsions would be met with reciprocal action by Moscow.
Asked about the potential use of nuclear weapons in the Ukraine war, Dr Pavlovsky replied: "Our military doctrine sets the conditions and situations when nuclear weapons can be used by the Russian Federation."
Ukraine's Ambassador to Australia Vasyl Myroshnychenko said the number of Russian diplomats accredited in Australia should match the number of Australians in Moscow.
"It is called reciprocity," he wrote on Twitter.
"How many RU diplomats work in AU ? European nations have expelled over 500 Russian diplomats."
Mr Myroshnychenko also re-posted a video showing a donated Australian Bushmaster towing a captured Russian armoured personnel carrier.
"Good morning fellas! Isn't it beautiful?," he tweeted.
ANU International Security Professor John Blaxland has warned the upcoming northern hemisphere winter will be "ugly".
"We are looking down the barrel of an extended conflict," he told Nine.
"Neither side looks likely to back down. Ukraine is getting continued support from the West ... and in the meantime, the Russians are recruiting 300,000 or more soldiers that will trickle in the coming months."
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