Bank of Japan policymakers have raised concerns about the nation's slowing exports, with some citing "structural factors" that might not be addressed in the near term, according to the minutes of their meeting released Friday.

The central bank's nine-member Policy Board agreed that exports "had leveled off more or less" but expects them to "increase moderately, mainly against the background of the recovery in overseas economies," the minutes of the June 12 to 13 meeting said.

But looking into why exports lack momentum, a few members "pointed to the possibility that structural factors . . . could be influencing exports to a larger degree than had been expected."