The nation's monetary base edged up 1.7 percent in June from a year earlier for its 53rd straight month of expansion, the Bank of Japan said Monday.

The average daily balance of the monetary base -- cash in circulation plus current-account deposits held at the central bank by financial institutions and Japan Post -- came to 109.159 trillion yen in June, the BOJ said.

The monetary base has continued to grow thanks to the central bank's ultra-loose quantitative easing policy.