Prime Minister Scott Morrison says Russia has launched a "brutal" and illegal invasion of Ukraine that will be met with a severe response by Australia and the international community.
"I will call it what it is: the Russian government launched a brutal invasion, unprovoked, on Ukraine and should be condemned for doing so," Mr Morrison said.
The Ukrainian interior ministry said an invasion has begun, after Russian President Vladimir Putin publicly authorised a military operation in Ukraine's Donbas region.
The Russian defence ministry has confirmed missile strikes against Ukrainian military and aviation targets, with reports of explosions in several cities and troops entering Ukrainian territory.
Mr Morrison said Russia was breaching international law and the UN charter by invading Ukraine.
United States President Joe Biden released a statement saying the US and its allies would respond in a "united and decisive" way.
"President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering," Mr Biden said.
"Russia alone is responsible for the death and destruction this attack will bring.
"The world will hold Russia accountable."
Mr Biden said he would meet with his G7 counterparts in the morning before announcing further consequences for Russia.
Opposition Leader Anthony Albanese said the invasion marked "a grave moment for humanity".
"This is not just an attack on Ukraine, it is also a contemptuous attack on one of the core principles of the post-World War II order," he said in a statement.
Mr Morrison said Russia's attempts to justify the invasion were unconvincing.
"Vladimir Putin has fabricated a feeble pretext on which to invade. Russia’s disinformation and propaganda has convinced no-one," he said.
More sanctions imposed on Russian individuals
Yesterday, the federal government announced it would join the US, the United Kingdom and others to impose a raft of sanctions on the separatist regions of eastern Ukraine and specific sanctions and travel bans on eight Russian individuals on the nation's security council.
Mr Morrison said sanctions would be extended to another 25 individuals, including army commanders, deputy defence ministers and Russian mercenaries, as well as four entities involved in the development and sale of military technology and weapons.
He said further waves of sanctions were expected, including on the 300 members of Russia's parliament.
"[Sanctions] do have an impact on those individuals, particularly when they're done in concert with other countries," Mr Morrison said.
"That's why I think it's important that all countries engage in these sanctions against these individuals. It sends a very clear message.
Russia's ambassador Alexey Pavlovsky was called in to the Department of Foreign Affairs and Trade yesterday, where he was dressed down over Russia's actions.
In response, the Russian embassy labelled the sanctions "xenophobic" and accused Canberra of supporting Ukrainian bullies hindering the independence of breakaway regions.
"In alignment with its key partners, Canberra has played its part in supporting and encouraging the xenophobic bullies based in Kyiv," it said.
"Recognising the Donetsk and Luhansk people's republics was the only solution Russia felt compelled to take."
This morning, Mr Morrison said he completely rejected the statement from the embassy and doubled down on the need for the sanctions to send a message to the Russian government.
"There must be a price for the unprovoked, unlawful, unwarranted, unjustified attacks and threats and intimidation that has been imposed by Russia on Ukraine," Mr Morrison said.
He said Russian claims that troops had entered Ukraine on a peacekeeping mission were false.
