TOKYO, April 2 (Reuters) - Japan's monetary base expanded 1.6% in March from a year earlier, marking the fifth straight month of slowdown in the annual pace of increase in a sign the central bank was steadily dialling back its massive stimulus.

The March increase followed a 2.4% gain in February, Bank of Japan (BOJ) data showed on Tuesday.

The BOJ ended eight years of negative interest rates and other remnants of its unorthodox policy last month, making a historic shift away from its focus on reflating growth with decades of massive monetary stimulus.

(Reporting by Leika Kihara Editing by Shri Navaratnam)