Almost three decades after Ronald Reagan, Barack Obama is set to repeat a feat that not many US Presidents get the privilege of -- being sworn in twice.

The President will be sworn in twice for his second term by Chief Justice John Roberts -- first today and for a second time tomorrow.

The two oath takings have been necessitated as the US Constitution-mandated date of January 20 this year fell on a Sunday and historically inaugural ceremonies are not held on Sundays because Courts and other public institutions are not open.

Therefore, this year, in accordance with the requirements of the US Constitution, Obama and Vice President Joe Biden will officially be sworn in on a Sunday.

The following day, a ceremonial swearing-in that is open to the public will take place on the West Front of the United States Capitol, the Presidential Inauguration Committee has said.

The US Chief Justice Roberts will administer the oath of office for Obama at the Inaugural swearing-in ceremonies on both the days and Supreme Court Associate Justice Sonia Sotomayor will administer the oath of office to Biden.

Obama has selected historical bibles including those used by Abraham Lincoln and Martin Luther King for his swearing in ceremonies.

"I will be honoured to again stand on the Inaugural platform and take part in this important American tradition," Obama said earlier this month.

"I look forward to having Chief Justice John Roberts administer my oath of office as we gather to celebrate not just a president or vice president, but the strength and determination of the American people," he added.

Presidents Dwight D Eisenhower and Ronald W Reagan also had two ceremonies, one private swearing-in on a Sunday and a public oath ceremony on the following Monday.