Japan "need not worry" about China's devaluation of the yuan because it can always offset the effects by easing monetary policy, said an adviser to Prime Minister Shinzo Abe.

Depreciation in China's currency tends to boost the yen, and if external demand weakens too much the Bank of Japan may increase monetary stimulus, said Koichi Hamada.

"The magnitude of China's shock is much larger than that from Greece, but we need not worry because always the effect of Chinese devaluation can be offset" by monetary easing in Japan, Hamada said.