US President Donald Trump's refusal to concede the US election will reflect poorly on his place in history, President-elect Joe Biden said on Tuesday.

"I just think it's an embarrassment, quite frankly," Biden told reporters when he was asked about Trump's refusal to acknowledge defeat in the November 3 election.

"How can I say this tactfully," Biden said. "I think it will not help the president's legacy." The president-elect downplayed any practical problems caused by Trump's refusal to help with the transition toward a new US administration. He said the transition process was "well underway" and "nothing's going to stop that."

Much formal transition work doesn't begin until the administrator of the federal General Services Administration ascertains the "apparent successful candidate" in the general election. This has not happened yet amidst legal challenges by President Donald Trump's team to the election results in some states. This means Biden is not receiving a daily classified briefing on security threats typically afforded to the president-elect.