The yen's depreciation against the U.S. dollar is "rapid and one-sided," Japan's top currency diplomat Masato Kanda said Monday, after the U.S. currency hit a seven-month high in the 143 zone.
Asked about the possibility of Japanese authorities stepping into the foreign exchange market, Kanda, vice finance minister for international affairs, told reporters, "No options are ruled out."
The yen's decline reflects the widening of the interest rate gap between Japan and the United States. The Japanese currency has also weakened relative to the euro.
The yen has approached the psychologically important 145 mark, leaving some currency traders alert for possible verbal warnings by Japanese authorities and the possibility of a yen-buying, dollar-selling intervention to arrest the currency's decline.
Kanda said excessive volatility is "not good" for the economy, adding, "We will continue to watch developments closely with a sense of strong vigilance."
Japan conducted interventions in September and October with the intent to stop the yen's sharp fall against the U.S dollar but has since refrained from taking further action.
The renewed yen-selling pressure came as the Bank of Japan has stuck to its ultralow rate policy, in stark contrast with its peers like the Federal Reserve and the European Central Bank which are expected to continue raising interest rates.