The US Congress formally certified Republican President-elect Donald Trump's election victory on Monday during a session presided over by Democratic Vice President Kamala Harris, who lost the November contest.

The quadrennial ritual, clearing the way for Trump's inauguration in two weeks, went smoothly - in sharp contrast to four years ago when Trump supporters stormed the Capitol in a failed bid to block the certification of then-President Trump's 2020 loss to Democratic President Joe Biden.

Trump continues to falsely claim that his 2020 defeat was the result of widespread fraud, and had warned throughout his 2024 campaign that he harboured similar concerns until his November 5 defeat of Harris.

Harris oversaw the roll call of the states in the vice president's ceremonial role as president of the Senate.

"Congress certifies our great election victory today - a big moment in history. MAGA!" Trump wrote on his social media platform Truth Social earlier on Monday.

The joint session of Congress proceeded despite a winter storm that dropped about 15 centimetres of snow.

The final certification backed up preliminary findings that Trump won 312 Electoral College votes to Harris's 226.

Republicans also captured a majority in the US Senate and held a narrow edge in the House in November's election, which will give Trump the party support he needs to implement his planned agenda of tax cuts and a crackdown on immigrants living in the country illegally.

Democrats did not try to block certification of Trump's victory on Monday.

Security inside and outside the Capitol was heightened in preparation for the certification and was expected to remain in place through Trump's swearing-in on January 20. (Reuters)