Japan's wholesale inflation jumped in May at the fastest annual pace in nine months, data showed Wednesday, in a sign the weak yen was adding upward pressure on prices by pushing up the cost of raw material imports.

The data complicates the Bank of Japan's decision on how soon to raise interest rates, as price rises driven by cost pressures could cool consumption and dampen the chances of achieving the kind of demand-driven inflation it wants to see before further phasing out stimulus, analysts say.

"Consumer inflation may not slow much as wholesale price rises reaccelerate, and energy prices are seen rising sharply towards this summer" as government subsidies to curb utility bills end in June, said Takeshi Minami, chief economist at Norinchukin Research. "But the BOJ will need to wait for wages to rise and help consumption recover" before raising rates again, he added.