* Risk aversion behind current yen moves - Shirakawa
* BOJ to continue efforts to beat deflation - Shirakawa
By Leika Kihara
TOKYO, May 24 (Reuters) - Bank of Japan Governor Masaaki Shirakawa stressed on Thursday the central bank's resolve to maintain its ultra-loose monetary policy, but ruled out easing solely for the purpose of weakening the yen.
Shirakawa said there was no clear historical evidence that an expansion in Japan's monetary base leads to a weaker yen, countering views that the central bank can directly push down the yen by pumping more money into the economy.
"The biggest factor affecting currency moves now is investors' risk aversion," Shirakawa told a lower house parliamentary committee, stressing that monetary policy alone cannot influence yen moves.
The BOJ eased monetary policy in February and set an 1 percent inflation target to show its determination of beating deflation that has plagued Japan for more than a decade.
It followed up with more monetary easing in April but has remained under political pressure for further action to support the economy and ease the pain from a stubbornly strong yen.
Having pledged to pursue powerful monetary easing until 1 percent inflation is in sight, the BOJ will continue efforts to beat deflation with its asset-buying programme, its key monetary easing tool, Shirakawa said.