Rejecting China's call for a new global currency as an alternative to the dollar, the US President Barack Obama has said that green buck is 'extraordinarily strong'.

"As far as confidence in the US economy or the dollar, I would just point out that the dollar is extraordinarily strong right now," Obama told a crowded press conference at White House on Tuesday.

"I don't believe that there's a need for a global currency," he said.

"The reason the dollar is strong right now is because investors consider the US the strongest economy in the world, with the most stable political system in the world," he replied in response to a question.

"So you don't have to take my word for it. I think that there is a great deal of confidence that ultimately, although we are going through a rough patch, that the prospects for the world economy are very, very strong," Obama said.