Japan's fears over China's status as a rival for economic supremacy in Asia are misplaced, according to the chief economist at the Asian Development Bank.

"If anything, Japan's major competition is (South) Korea, not China," Ifzal Ali said in a recent interview. "It will be a long time before China becomes a rival, especially if Japan gets out of its 10-year stupor and starts growing at a rate of 2 percent to 3 percent."

China's current growth of 8 percent to 9 percent is also not sustainable, Ali said, predicting that growth will slow in the next two to three years.