The U.S. currency rose to 146.35 yen , a level not seen since August 1998 during the Asian financial crisis, moving above levels that triggered intervention by Japanese authorities last month to stem excessive yen weakening.
The yen was trading around 146.30 to the dollar around midday on Wednesday as traders braced for U.S. inflation data and its implications on future U.S. rate hikes.
Neither Matsuno nor Suzuki used stronger expressions in describing yen moves on Wednesday such as "excessive," "one-sided" or "speculative," suggesting that currency intervention may not be imminent.
Last month, Japanese authorities sold dollars and bought yen in a market intervention for the first time in 24 years, spending 2.8 trillion yen ($19.2 billion) to slow a rapid slide in the yen that was considered a threat to the economy.
Investors see solo action by Japan being far less effective than concerted intervention.