The risks are piling up for Japan's construction equipment makers in the aftermath of Brexit.

Already contending with China's slowdown and a rout in commodities prices, Hitachi Construction Machinery Co. now faces two new threats after the U.K.'s vote to quit the European Union: the yen's rapid appreciation and fears that Brexit could hit demand in Europe, according to its chief executive officer.

"The yen has been strengthening sharply and that's the biggest impact on our business," Yuichi Tsujimoto said in an interview Tuesday. "Immediate risks are the currency movement and the European economy."