Elon Musk, the world’s richest man, challenged a United Nations official’s claim that just a small percentage of his wealth could help solve world hunger.

Musk was responding to comments by David Beasley, director of the UN’s World Food Programme, who repeated a call last week following an earlier tweet this month asking billionaires like Musk to "step up now, on a one-time basis.”

Beasley specifically called for action from Musk and Amazon.com Inc co-founder Jeff Bezos, the two men atop the Bloomberg Billionaires Index. Just US$6bil could keep 42 million people from dying, Beasley said.

If the World Food Programme, using transparent and open accounting, "can describe on this Twitter thread exactly how $6B will solve world hunger, I will sell Tesla stock right now and do it,” Musk wrote in a Twitter post.

Musk is CEO of the electric-vehicle company, which last week joined the handful of companies valued at more than US$1 trillion .

The US$6bil amount would be just a small fraction of Musk’s current net worth of US$311bil - and less than the US$9.3bil his wealth increased on Oct 29 alone, according to the billionaires index.

 - Bloomberg