Prime Minister Scott Morrison has condemned the "brutal" and "unprovoked" Russian invasion of Ukraine and announced another tranche of sanctions.
A further 25 Russians, including army commanders, deputy defence ministers and mercenaries responsible for the attacks will be sanctioned as will four additional financial institutions.
"We must ensure there is a cost for this violent, unacceptable, and egregious behaviour," Mr Morrison said.
"There will be further waves of sanctions as we identify those responsible for these egregious acts, including moving on over 300 members of the Russian parliament."
The prime minister denounced "unilateral, hostile actions" by the Kremlin as he addressed reporters in Sydney hours after Russian President Vladimir Putin announced a special military operation in Ukraine's Donbas region.
"The Russian government launched a brutal invasion - unprovoked - on Ukraine," he said.
"Russia has chosen war."
Mr Morrison again declined to elaborate on what technical military support Australia would engage in after ruling out troops on the ground.
"We are involved with our partners in these types of activities, but it wouldn't be appropriate for me to go into detail."
He said there has been no change in the decision to not expel the Russian ambassador.
"But you can be in no doubt about the very stern messages that have been sent to the ambassador on behalf of the Australian government," he said.
Explosions could be heard in Ukraine's capital Kyiv, and Russia's defence ministry has since said it was using "high-precision weaponry" to target military infrastructure and air defences without risking the civilian population.
There are reports of rocket attacks in the capital and military jets being targeted on the city's outskirts, with hundreds of casualties from the initial strike.
Ukraine has called the movement a full-scale invasion.
In an online video, President Volodymyr Zelenskyy declared martial law and said Russia was targeting military installations across the country.
Russian troops have also reportedly been joined by Belarusian troops, with clashes along Ukraine's northern border with Belarus.
Earlier in the day, Mr Morrison formally signed off on the first tranche of sanctions against Russia.
The sanctions, aimed at Russian banks and individuals of strategic and economic importance, will become law from Friday and come into effect at the end of March.
Mr Morrison said the sanctions would send a message about the cost of Russia's aggression.
"It's important that all countries engage in these sanctions against these individuals," he said.
"It sends a very clear message. You sanction, support, benefit from this type of violence, then you will be isolated, you will be targeted."
Opposition Leader Anthony Albanese says Mr Putin's decision marked a grave moment for humanity and joined the government's condemnation.
"This attack is wholly unprovoked and without justification. All Australians stand with the people of Ukraine, and are united in condemnation of Russia's shameful act of aggression," he said.
"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. Australia must stand united with our allies in holding Russia to account."
Russia's ambassador hit back at the sanctions, accusing Australia of being indifferent to discrimination faced by Russian speakers.
In a statement, the embassy said the decision to recognise the Donetsk and Luhansk regions on humanitarian grounds was made to "protect" civilians, including hundreds of thousands of Russian nationals.
But Mr Morrison said any suggestion from Russian ambassador Alexey Pavlovsky that Russian troops in Ukraine were peacekeepers was "offensive" to legitimate peacekeeping forces.
"They're not peacekeepers, they're invaders. That's how we see it and we'll call it out. If they don't like it, that's tough."
More than 180 Australian citizens in Ukraine have requested assistance to leave the country and an estimated 1400 Australians remain there.
with reporting from Reuters
