Business leaders in the Kansai region have issued a warning to Bank of Japan Gov. Haruhiko Kuroda that the yen's slide to a six-year low is raising the cost of importing raw materials and fuel, which could spell trouble for the economy.

Firms in the city of Osaka say the higher costs are eating into their profit margins because they can't pass them on even as sales rise, Osaka Chamber of Commerce and Industry Chairman Shigetaka Sato told Kuroda on Tuesday.

Kansai Economic Federation Chairman Shosuke Mori said the rise in fuel costs warrants close monitoring.