Suzuki, speaking to reporters, declined to comment when asked whether authorities are conducting stealth intervention to support the weakening currency.
“We cannot tolerate excessive currency moves driven by speculators,” Suzuki said.
“We are closely watching currency moves with a sense of urgency.”
Japan spent 2.8 trillion yen ($18.81 billion) in dollar-selling, yen-buying intervention last month when authorities intervened to prop up the yen for the first time since 1998.
Speculation lingers that Japanese authorities may have intervened in the market since then without announcing, but Suzuki declined to comment.
“Generally speaking, there are times when we intervene by making announcement and some other times when we do without it,” Suzuki said, declining to comment further.
($1 = 148.8400 yen)