The government must take steps as needed against excessive declines in the yen, Deputy Chief Cabinet Secretary Seiji Kihara said on Sunday, repeating authorities' warnings about the currency's slide to 24-year lows.

"As for excessive, one-sided currency moves, we will closely watch developments and must take steps as needed," Kihara told a television program, when asked about the yen's recent falls.

The yen has recently fallen to 24-year lows against the dollar as investors focus on the widening divergence between the U.S. Federal Reserve's aggressive interest rate hikes and the Bank of Japan's pledge to maintain ultralow rates.