Donald Trump offered US President Obama $5m in exchange of his College and passport records (Reuters)

Billionaire Donald Trump's "bordering on gigantic" revelation about US President Barack Obama turned into a damp squib.

After triggering an internet frenzy by claiming to have information so big it might change the course of the US presidential elections, the eccentric real estate magnate's video "revelation" on his Facebook and Twitter pages revealed nothing new at all.

Since Trump announced his so-called bombshell on Monday, there was wild speculation that he would publish proof of Michelle Obama's alleged intention to divorce her husband or "evidence" that Barack Obama sold and used cocaine at college.

Trump instead picked up the old story of the alleged mystery of the president's past by repeating claims that Obama was born in Kenya and therefore not qualified to be president of the United States.

When the claims gained ground a year ago, Obama responded by producing his long form birth-certificate, which made clear he was born in Honolulu, Hawaii. He dismissed Trump as a "carnival barker".

"We do not have time for this kind of silliness," said Obama. "We have better stuff to do. I have got better stuff to do. We have got big problems to solve. We are not going to be able to solve our problems if we get distracted by sideshows and carnival barkers," Obama said.

Trump claimed credit for Obama publishing his birth certificate but said in his new video release that he wanted more: the president's college and passport records and applications, for which he would pay $5m to go to a charity of Obama's choice.

Trump set a deadline of 5pm on 31 October.

The billionaire claimed to have been pushed to make the offer by "millions of people" who have contacted him "via email and social pages, seeking my assistance to have this extremely important issue settled once for all".

For the record, Obama majored in political science at New York Columbia University before graduating with a JD magna cum laude at Harvard Law School in 1991.