TOKYO, Dec 27 (Reuters) - Japanese government bond yields fell on Wednesday as investors failed to see signs of a shift in the Bank of Japan's (BOJ) policy from a summary of opinions at this month's meeting.

The 10-year JGB yield fell 2.5 basis points (bps) to 0.605%. The 20-year yield fell 2 bps to 1.350%.

A summary of opinions showed that the nine BOJ board members were split between caution about raising interest rates, and the need to start preparing for a future exit.

"The overall tone of the meeting offered no clue on when the BOJ would end its negative rate policy," said Keisuke Tsuruta, senior fixed income strategist at Mitsubishi UFJ Morgan Stanley Securities.

"The investors' caution for finding a clue on the policy shift was so strong, they suffered a disappointment when they found no clue, which prompted them to buy bonds."

The BOJ maintained its ultra-loose policy settings this month, and made no change to its dovish policy guidance.

Market players also saw no hints from Governor Kazuo Ueda on when the central bank would make a policy tweak from his post-meeting briefing, or in his latest speech on Monday.

Takeshi Ishida, strategist at Resona Holdings, said he expects the BOJ could end the negative rate policy next month, as Ueda's outlook for the Japanese economy is positive.

Ueda said on Monday the likelihood of achieving the BOJ's inflation target was "gradually rising."

The 30-year JGB yield fell 1.5 bps to 1.580%.

The two-year yield fell 1 bp to 0.055%, while the five-year yield fell 2.5 bps to 0.215%. (Reporting by Junko Fujita; Editing by Varun H K)