Bank of Japan Governor Haruhiko Kuroda warned of the potential dangers of heavy money printing, saying that financial bubbles, when accompanied by excessive lending by commercial banks, tend to trigger financial crises.

Kuroda said the G20 members must focus on implementing the financial reforms they launched in 2009 to prevent another financial crisis.

"Financial bubbles tend to associate with financial crises when accompanied by excessive credit creation," Kuroda said.

"Our experience of Japan's crisis in the late 1990s and of the last global financial crisis in the late 2000s reminds us that the most important role of financial regulation and supervision is to address market failures in order to prevent financial crises," he added.