TOKYO (Kyodo) -- Japan's finance chief said Friday he is concerned about the impact of the recent rise in the key long-term government bond yield on fiscal spending, while the central bank governor signaled readiness to increase debt purchases if needed to curb a sharp rise.

With the benchmark 10-year Japanese government bond yield hitting a 15-year high, Finance Minister Katsunobu Kato said the rise could strain government spending by increasing interest payments.

Market expectations for a sooner-than-expected interest rate hike by the Bank of Japan sent the bond yield to 1.440 percent on Thursday, the highest level since November 2009.

"In an exceptional situation, such as a sharp rise (in bond yields), we will flexibly increase our bond purchases," Ueda said in a parliamentary session. "We will carefully monitor the market and make a judgment" on the timing for additional bond buying."

Expectations for a BOJ rate hike eased somewhat in financial markets on Friday following the comments.

In July 2024, the central bank reduced its monthly government bond purchases as part of its efforts to normalize monetary policy.

However, the BOJ said at that time that in the case of a rapid rise in long-term bond yields, it will make "nimble responses" by increasing bond buying.

Ueda also warned that higher long-term yields would reduce the value of government bonds held by companies and other entities. Bond yields move inversely to prices.

At a news conference earlier in the day, Kato said, "As we have a high debt-to-GDP ratio, there is a risk of straining our policy costs," referring to the country's total debt, which is twice the size of its gross domestic product.

The rate hike expectations also sent the yen to around a two-month high against the U.S. dollar in the 149 zone.

Kato declined to comment on the yen's movements, saying only, "Our view on foreign exchange has not changed."