Japan's most closely watched gauge of money supply grew 1.7 percent in June on a year-on-year basis, following a 1.5 percent rise in May, the Bank of Japan said in a preliminary report Friday.

The average daily balance of M2 plus certificates of deposit came to 704.2 trillion, yen up from a revised 704 trillion yen in May. M2 consists of cash in circulation, demand deposits and quasi-money.