By Leika Kihara

TOKYO Bank of Japan (BOJ) Governor Kazuo Ueda said on Friday the central bank is unwavering in its stance of patiently maintaining ultra-loose monetary policy given "extremely high" uncertainty over the economic outlook.

The recent rise in inflation above the BOJ's 2% target is driven mostly by external, cost-push factors rather than strong domestic demand, Ueda said, adding that responding to such price increases with tighter monetary policy would hurt the economy.

"At present, it's necessary to continue with monetary easing," as Japan's economy faces risks from slowing global growth and uncertainty on whether wage rises will be sustained, he said in a speech at a seminar.

"The cost of prematurely shifting policy, and nipping the bud towards achieving 2% inflation, is extremely large," Ueda he said. "It's appropriate to take time judging (when to) tweak ultra-easy policy toward a future exit."