The nation's most closely watched money supply gauge grew 1.8 percent in June from a year earlier, the Bank of Japan said in a preliminary report Tuesday.

The pace of growth in the average daily balance of M2 -- cash in circulation, demand deposits and quasi-money -- plus certificates of deposit, grew for the second straight month, following a 1.6 percent increase in May.

The average daily balance of M2 came to 681.3 trillion yen in June, up from a revised 680.2 trillion yen in May.

The balance of quasi-money, mostly in time deposits, fell 0.8 percent to 316.3 trillion yen. But the margin of decline was smaller than a revised 1.1 percent fall in May.

Quasi-money refers to time deposits and other types of savings at banks that cannot immediately be cashed, including foreign currency deposits and nonresidents' yen deposits.

A breakdown of the data shows that cash in circulation increased 5.1 percent to 66.8 trillion yen, following a revised 4.9 percent gain in May, and that demand deposits -- ordinary deposits and checking accounts -- rose 4.6 percent to 280.0 trillion yen following a revised 4.8 percent gain in May.

The balance of M1 grew 4.7 percent to 346.8 trillion yen, following a 4.8 percent rise in May. M1 refers to cash in circulation plus demand deposits.