Japan to act when required against volatile currency moves: finance chief

Speaking to reporters, Katayama reiterated that the government could take "decisive action" but did not disclose details, with the yen trading near the 160 line against the U.S. dollar, a level that raises market vigilance about an intervention by Japanese authorities.

Katayama said the government continues to hear strong views that "volatility in the crude oil futures market is extremely high," which heightens speculative moves in the currency market.

Financial markets are bracing this week for a series of policy-setting meetings by major central banks, including the Bank of Japan, at a time when uncertainty remains over the outcome of the conflict. 

While Katayama is set to embark on a five-day trip to Uzbekistan from Saturday, the government will still be prepared to act if necessary.

She is scheduled to attend the Asian Development Bank's annual meeting and related gatherings with Southeast Asian countries, South Korea and China. Japanese financial markets will be closed during this time due to the Golden Week holidays in early May.

As noted earlier, crude oil procured from the United States by Japanese oil distributor Cosmo Oil Co. arrived in Japan last Sunday for the first time as an alternative supply, following the start of U.S. attacks on Iran in late February.