Consumer prices declined in June for the fifth month in a row, undermining the Bank of Japan's case that inflation will take hold and interest rates need to be raised.
Core consumer prices, which exclude fresh food, fell 0.1 percent from a year earlier, the Internal Affairs and Communications Ministry said Friday.
BOJ Gov. Toshihiko Fukui said this month that core prices will "definitely" increase in the long term and the bank should raise the key rate if it's confident about the prospects for growth. Fukui has said keeping the key rate at 0.5 percent, the lowest among Group of Seven nations, for too long may overstimulate the economy and hamper a sustained expansion.