Bank of Japan Governor Kuroda Haruhiko says the rapid weakening of the yen is undesirable for the country's economy.
He made the remarks after the central bank decided to continue its massive monetary-easing program on Friday.
Kuroda said it is important for the exchange rate to remain stable.
He said the slide in the currency is making it difficult for companies to plan.
Kuroda said the BOJ will provide strong support for the economy by persisting with its monetary easing.