The Bank of Japan should pay close attention to currency levels because its efforts to hold down interest rates are weakening the yen, according to a senior member of the Japanese ruling coalition party Komeito.

"From the point of view of the economy, I understand why they are holding down interest rates,” said Keiichi Ishii, secretary-general of Komeito, the junior partner to Prime Minister Fumio Kishida’s ruling Liberal Democratic Party.

"But the side effects of that are reflected in exchange rates,” he said in an interview with Bloomberg News in Tokyo on Friday. "How far can the side effects be tolerated? If the yen goes too low, things will be tough, so I want the BOJ to pay close attention to exchange rates.”