Now that the central bank has added negative rates to its record monetary stimulus program, it's time for the Abe government to double down on reform efforts, said Deputy Gov. Hiroshi Nakaso.

"The Bank of Japan has taken monetary easing one step further," Nakaso said in a speech in Okinawa on Thursday. "I expect the original third arrow of Abenomics, the growth strategy, to fly higher and faster."

Nakaso's comments come amid increasing concern that central banks around the world are reaching the limits of monetary policy and that governments need to shoulder a greater burden in building the foundations for economic revival. After more than three years of Abenomics, some of its early achievements — a weak yen, surging stocks and company profits — are being eroded as volatile global markets buffer economies around the world.