Senator Carr says he has received no hint from two discussions with American officials that they have a plan to extradite him to the US.
"There is not the remotest evidence that is the case," he told ABC Television on Sunday.
Assange has been at Ecuador's embassy in London for nearly a week as the South American nation considers his political asylum application.
The asylum bid is a last-ditch effort to avoid extradition to Sweden to face sex-crime allegations he says are baseless.
The Australian-born 40-year-old fears removal to Sweden could pave the way for extradition to the US where he would face possible charges - and a possible death sentence - over the WikiLeaks' release of secret diplomatic cables.
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Senator Carr said the US had an opportunity to ask the UK government to extradite Assange over the two years the WikiLeaks founder has been in London.
"There is a view that it would be easier for the US to extradite him from the UK rather than from Sweden, where he is wanted for questioning about (matters) wholly unrelated to anything to do with WikiLeaks or state secrets," he said.
But Senator Carr said he is yet to receive a complete denial from US authorities that they are not interested in extraditing the Australian.
"They haven't been able to rule out that one corner of the American administration is considering it, but I would expect the US wouldn't want to touch this," he said.
He said the US government was aware that Australia did not want Assange extradited from anywhere.
"They know that's the well worn position of Australia," he said.
