Australians in Ukraine have been told to leave if it's safe to do so amid escalating concern about the threat of an invasion from Russia.
The Department of Foreign Affairs and Trade issued updated travel advice for Ukraine overnight, following talks with allies the US, UK and Canada.
Foreign Affairs Minister Marise Payne said the advice was the "appropriate thing to do to protect Australians", given flights could be cancelled at short notice.
"This is a cautious and prudent step, it is because the situation is unpredictable. And it's about protecting Australians on the ground," she told ABC's RN Breakfast.
There are about 1400 Australians in Ukraine, she said.
The federal government has directed the departure of families members of Australian embassy staff in Kyiv.
Australians should not travel to Ukraine, according to the new advice.
Senator Payne refused to speculate on the probability of a Russian invasion of Ukraine.
But she said the "clear diplomatic message" from Australia and its allies was that Russia should de-escalate the situation.
Russia has assembled an estimated 120,000 troops on the border with Ukraine according to reports.
Senator Payne said Russia's actions were an example of an "authoritarian regime ... trying to exercise their power, their aggression".
"It is not helpful to security and stability in any way, shape or form," she said.
Senator Payne said Australia would not become involved in any military intervention.
The comments came after US President Joe Biden directed the Pentagon to put about 8500 troops on standby for potential deployment to eastern Europe.
Pentagon press secretary John Kirby on Monday said no final decisions had been made on deployments, which he said would happen only if the NATO alliance decided to activate a rapid-response force "or if other situations develop" in connection with tensions over Russia's military build-up along Ukraine's borders.