Trade Minister Dan Tehan has warned Australia will enact strong economic sanctions against Russia if it invades Ukraine.

As tensions in the region heighten, Australian diplomatic staff have been evacuated from the Ukrainian embassy in Kiev.

It came after the US warned a Russian invasion of Ukraine appeared likely within days. However, American authorities have refused to confirm reports an attack is likely on Wednesday.

In Washington, President Joe Biden’s National Security Adviser Jake Sullivan said an invasion could begin “any day now”.

“We cannot perfectly predict the day, but we have now been saying for some time that we are in the window,” Mr Sullivan told CNN.

Mr Tehan said he hoped the situation in Ukraine would resolve peacefully, but measures would follow should Russia invade.

“It is highly likely there would be very strong sanctions against Russia and we’ll have to play our part in that regard,” he told Sky News.

“We want a de-escalation, but if [an invasion] happens, then you’ll be looking at sanctions and we’ll be a part of that.”

Mr Tehan said an invasion would also likely lead to an increase in oil and gas prices and put pressure on international markets.

Treasurer Josh Frydenberg said the situation in Ukraine had reached a “dangerous juncture”.

“It’s a very dangerous situation and the reverberations will be felt far and wide if, in fact, the Russians do invade,” Mr Frydenberg told the Nine Network.

“You don’t amass more than 100,000 troops on a border to check out the views or have a picnic.”

Australian diplomatic staff have been directed to a temporary office in Lviv.

Acting deputy secretary national security and international policy Rod Brazier told Senate estimates the final five remaining staff had arrived in Lviv, in Ukraine’s west, on Sunday.

“[On Sunday] morning, as a result of the threat to peace and stability in the region, the Australian embassy in Kiev was temporarily closed,” he said.

“The embassy has set up a facility for operations. This is a temporary move that will be kept under review considering the security situation.”

Mr Brazier said 147 Australian citizens, permanent residents and dependants remained in Ukraine.

The federal government has warning Australians in Ukraine to leave immediately in light of the situation.

Former US ambassador to Ukraine Steven Pifer said there had been a “startling build-up” of Russian forces on the Ukrainian border.

Moscow continues to deny any plans for an invasion, and has accused the West of “hysteria”.

“Washington has made a decision to assume the worst and then try to do everything it can to deter and dissuade the Kremlin from making a decision that would be a tragedy for Ukraine, but also a tragedy for Russia,” he told ABC radio.

US President Joe Biden and Russian President Vladimir Putin held crisis talks on Ukraine on Sunday.

Russia was warned during the meeting there would be “swift and severe costs” should an invasion happen.

Mr Biden also spoke to Ukrainian President Volodymyr Zelenskiy, who invited theUS President Joe Biden to visit Ukraine soon.

“I’m convinced that your arrival in Kyiv in the coming days, which are crucial for stabilising the situation, will be a powerful signal and contribute to de-escalation,” the Ukraine presidential office quoted Mr Zelenskiy as telling Mr Biden on Sunday.

The White House declined to comment on the invitation.

-with AAP