SAPPORO, Japan, June 6 (Reuters) - Bank of Japan board member Toyoaki Nakamura said on Thursday the central bank should not raise interest rates for the sole purpose of slowing the yen's declines.

"Sharp, one-sided declines in the yen are undesirable as they heighten uncertainty over the outlook," Nakamura told a news conference.

"But trying to deal with the weak yen with interest rate moves would have a negative impact on the economy," as higher borrowing costs would cool demand, he said. (Reporting by Leika Kihara; Editing by Muralikumar Anantharaman)