Russia is posing an immediate challenge not just to Ukraine but also to the rest of the world, including Australia, says the US Secretary of State Antony Blinken, who was speaking in Melbourne on Thursday.

Mr Blinken also said the US could have done a better job communicating with the French about America's nuclear submarine deal with Australia.

Asked whether Russia or China posed a bigger threat to global security, Mr Blinken told 7.30 they were "very different challenges". 

"Russia, right now, poses an immediate challenge, not just to Ukraine … but to some very basic principles that are relevant to the security not just to people in Europe, but throughout the world, including in Australia," he said.

"Principles like you can't just change the borders of another country by force. You can't decide for another country its choices, its policies with whom it will associate. You can't exert a sphere of influence that tries to subjugate your neighbours to your will. 

"Those are the basic principles that are at stake when it comes to Ukraine and Russia's aggression. And they're relevant right here in this part of the world, just as they are in Europe."

Regarding the challenges posed by China, particularly in the South China Sea, Mr Blinken said "what we are doing is standing up for the norms, the rules, the standards".

"This is not about standing against anyone in particular. It is about standing up for a rules-based order, making sure that we uphold those rules and principles if they're being challenged."

'Could have done a better job communicating with French'

When AUKUS was announced and Australia cancelled its submarine contract with France's Naval group, the French said they were blindsided by the move.

"At least, speaking for ourselves, the United States could have done a better job communicating with our French allies and partners on this," Mr Blinken said.

"But we are working incredibly closely together as partners. We're doing the same thing through NATO, with the European Union, the G7. And, so, I think the strength of that relationship with that partnership is as good as it's ever been."

Asked who first raised the idea of a security pact between the Australia, the UK and the US — including finding a way for Australia have nuclear submarines — Mr Blinken said "this is something that was raised early on by Australia, by the United Kingdom".

"And, of course, part of what we're doing around the world, as I said, is working to revitalise, to re-energise and, as necessary, to reinvent these alliances and partnerships.

"No one can say with certainty what the future would bring. We have to be grounded in the present … Ultimately, we're going to be judged, like anyone else is, by what we do and what we achieve."

Watch this 7.30 story on ABC iview.