US President Barack Obama has rejected China's call for a new global currency as an alternative to the US dollar, defending the dollar as "extraordinarily strong".

"I don't believe there is a need for a global currency," Obama told a White House press conference on Tuesday.

He said investors considered the United States to be "the strongest economy in the world" and it enjoyed a "great deal of confidence" from investors, even as it was reeling from a prolonged recession stemming from financial turmoil.

Zhou Xiaochuan, governor of China's central bank, had earlier called for a replacement to the dollar with a different standard to be run by the International Monetary Fund.

Zhou suggested the IMF's Special Drawing Rights, a currency basket comprising dollars, euros, sterling and yen, has the potential to act as a super-sovereign reserve currency, saying it would "remove the inherent deficiencies caused by using credit-based national currencies."

The debate over the dollar's role came ahead of the G20 summit of developing and industrialized nations scheduled to be held on April 2 in London, where world leaders and international organizations, including the IMF, are set to discuss reforming the world's financial system.