Wholesale prices, excluding the impact of last year's consumption tax hike, fell 2.2 percent in April from a year earlier for the six straight month of decline, the Bank of Japan said Friday, weighed down by the effects of a plunge in crude oil prices.
The index of corporate goods prices stood at 100.7 against the 2010 base of 100, the central bank said in a preliminary report.
Including the effect of the 3-percentage-point consumption tax increase to 8 percent in April last year, wholesale prices dropped 2.1 percent with the index standing at 103.6, registering the first decline since March 2013.
Prices for petroleum and coal products, which largely depend on energy imports, dropped 23.4 percent from a year earlier. Those for chemical and related products, usually subject to oil prices, slid 5.9 percent.
"Crude oil prices have rebounded since January, though they are volatile," a BOJ official said. "The move is likely to be reflected on prices though the timing and the significance are uncertain."
Prices for electric power, gas and water climbed 4.7 percent due to price hikes of electricity by utility firms.
There are also moves by companies to pass on rising material costs to products as a result of a weaker yen, the official added.
Prices for imports fell 9.5 percent and exports grew 3.2 percent last month from a year before in yen terms.
On a monthly basis, wholesale prices rose 0.1 percent in April following a 0.3 percent gain in March.