New economic and fiscal policy minister Seiji Maehara pledged a closer watch over the Bank of Japan to ensure it meets a 1 percent inflation goal, adding that purchases of foreign bonds may be a powerful tool for easing.

"Now I am in this position, I will scrutinize even more strictly" the BOJ's efforts to achieve its target, Maehara, 50, said Monday. If the BOJ's actions are insufficient, he said he will do more than "just talk."

Newly appointed Finance Minister Koriki Jojima, 65, said that central bank purchases of foreign bonds are an issue that "requires cautious handling and consideration," suggesting he may have less enthusiasm for the idea.