Japanese consumer inflation slowed further in August, official data showed Friday, stoking concerns about Tokyo's war on deflation.
The nation's core consumer inflation, stripping out volatile fresh food prices, was 3.1 percent year-on-year, the internal affairs ministry said.
That was below markets' median forecast of a 3.2 percent rise, despite a sales tax hike in April.
The government raised consumption tax from 5.0 percent to 8.0 percent on April 1, which drove up consumer prices.
But the boosting effect appears to be easing as inflation growth slowed from 3.3 percent in both July and June and a three-decade high of 3.4 percent in May.
Excluding the impact of the tax increase, the rise in core consumer prices was 1.1 percent, Dow Jones Newswires said, quoting a formula by the Bank of Japan (BoJ).
The rate is well short of the bank's ambitious 2.0 percent inflation target for next year.
"We believe that it (inflation) will moderate further towards year-end," Capital Economics said in a note.
"This should increase pressure on the BoJ to provide more stimulus," it added.
"A more rapid pace of asset purchases may still eventually be required. We believe that the April meeting is probably the most likely venue to announce any expansion in stimulus," Capital Economics said.
Friday's data also showed inflation in the central Tokyo area, a leading indicator for the national trend, was an estimated 2.6 percent in September from a year earlier, while prices slipped 0.1 percent from August, the first dip in eight months.
The BoJ is to release a closely watched quarterly business sentiment report on Wednesday.
The bank unleashed massive easing measures last year as part of a wider government push to conquer years of debilitating deflation.
The tax hike was seen as crucial to help shrink Japan's mammoth national debt, proportionately the worst among wealthy nations.
However, there are fears it will derail economic recovery by taking a bite out of consumer spending.
"Consumer sentiment could have a double-dip toward the (March) end of fiscal year" due partly to a peak out of the labour market, Credit Suisse research analyst Hiromichi Shirakawa said.
"The Japanese economy would go back to a deflationary state by the second half of fiscal 2015" if the central bank, out of caution against further weakening of the yen, decided against putting yet more money into the markets, he said in a note.
The yen has been around at its lowest level in six years against the dollar on expectations of higher US interest rates.
While a weak yen is positive for Japanese exports, it pushes up import costs, eventually hitting consumers.