Nobuyuki Nakahara, a dissident member of the Bank of Japan's policymaking board, said Tuesday that the central bank should begin purchasing foreign bonds in an attempt to devalue the yen.

A devalued yen would help exporters sell their products abroad by making them less expensive and protect the domestic market from imports, which would grow more expensive.

"It is time to look for new means to adjust monetary policy, and the first of these should be the purchase of foreign bonds," Nakahara said in a speech in Tokyo, adding that such purchases were legally feasible.