Bank of Japan board members said Tuesday they will gradually raise interest rates on the basis of economic and price moves, although the bank can keep very low interest rates for the time being, the BOJ's semiannual outlook report released Tuesday said. The report, whose main conclusions closely followed the previous report issued half a year earlier, didn't build a fresh case for the BOJ to raise rates again this year. "The Bank will adjust the level of interest rates gradually in the light of developments in economic activity and prices while maintaining the accommodative financial conditions ensuing from very low interest rates for some time," the BOJ said in the semiannual "Outlook for Economic Activity and Prices" report. In the BOJ's semiannual report, the board members' forecasts for the core consumer price index next fiscal year centered on a 0.5% rise from this fiscal year, slowing from a 0.8% gain that they expected in April. The drop in on-year change forecast is due mainly to a revision of calculating the method of consumer prices by the government in August. The government has changed the base year for calculating the index to 2005 from 2000. The revision, which is implemented every five years, is expected to have pushed down consumer prices by 0.20-0.30 percentage point from the index that was calculated under the old method. The CPI forecast wouldn't be enough for the BOJ to rush into raising interest rates. Their forecasts for on-year changes in the core CPI for the next fiscal year, excluding the highest and lowest views, are in a core range between a 0.4% rise and 0.5% rise.