National Security Advisor Susan Rice admitted Monday that passing a landmark trans-Pacific trade agreement is now a "challenge," but it remains in the US strategic interest.

President Barack Obama has championed the 12-nation Trans-Pacific Partnership (TPP), but President-elect Donald Trump has pledged to scrap it, saying it would cost American jobs.

"TPP is obviously a challenge at this stage," Rice told AFP, warning that a failure to pass the deal would leave a vacuum.

"Trade is not going to stop, it will continue, we'll be part of it but we won't be as able to shape the framework to serve our values and our interests," she said.

"That leaves a vacuum for countries like China and others to fill -- that is not in our interest."