The disappointing data marked the latest red flag for the world's number three economy, and will put officials under ever-more pressure to find a way to kick-start growth, AFP reported.
Government figures showed that household spending in August shrank 4.6% from a year ago, way below expectations for a drop of around 2%.
Core consumer prices, excluding volatile fresh food prices, fell for the sixth straight month, dropping 0.5% on-year—way below the BoJ's 2% inflation target.
However, the labor market remained tight with unemployment at a multi-decade low of 3.1% while factory output rose a stronger-than-expected 1.5% last month.
"The continued decline in underlying inflation should ring the alarm bells at the Bank of Japan," said Marcel Thieliant at research house Capital Economics.
"Looking ahead, we expect underlying inflation to fall further to zero in coming months, which indicates that the Bank of Japan still has plenty of work to do to reach its 2% inflation target."
Japanese officials are under intense pressure to deliver, as many economists increasingly write off Prime Minister Shinzo Abe's spend-for-growth policy to fire up the economy, dubbed Abenomics.
Admission of Defeat
Last week, the BoJ, which launched a massive bond-purchase program to stimulate growth, revealed yet another exotic weapon in its monetary policy arsenal. After a hotly anticipated meeting, the bank said it would switch its emphasis from interest rates and concentrate its firepower on 10-year government bonds.
Governor Haruhiko Kuroda said the bank would buy as many or as few of these benchmark instruments as necessary to ensure the yield—the interest rate paid to holders—remained steady at around zero.
The bank said it would cut back on the number of longer dated bonds the bank holds. That should reduce the price of long-term securities, which—in turn—should increase their yield.
It was the latest effort to convince Japanese consumers that the price of goods and services will rise in the future.
Some analysts, however, said the move was an admission of defeat and a warning of the limits of central bank power, according to Financial Tribune.
Red Tape
On the government side, Tokyo in July announced a whopping 28-trillion-yen ($280-billion) package aimed at kick-starting growth, after Britain's June vote to quit the European Union sent financial markets into a tailspin and sparked a yen rally.
But Abe's promises to cut through red tape have been slower, and his plan to buoy Japan's once-booming economy has looked increasingly unrealistic.
Japan's economy contracted in the last three months of 2015, before bouncing back in January-March with a 0.5% rise on-quarter and then a 0.2% expansion in April-June.
Friday's data come ahead of the BoJ's closely watched Tankan quarterly business sentiment survey, due Monday. Economists expect the headline confidence index among large manufacturers to tick up in the October report, according to a Bloomberg survey.
Desperate for Farmers
The Japanese government will begin discussions to attract experienced farmers from abroad to a country now suffering from serious labor shortages in the agriculture industry, Nikkei reported.
The special government program would accept workers with certain skills and experience in agriculture. They would be allowed to work in special strategic zones where restrictions on foreign labor could be relaxed.
The agriculture experts would be paid equal to or higher than their Japanese peers.
So far, government efforts to attract skilled foreign workers have been focused on jobs in urban areas. The government now wants to broaden its scope to rural areas, many of which are suffering from weak economies.
The discussions will start on Tuesday at a council meeting for national strategic special zones. Several local governments have already submitted proposals to the working group regarding foreign agricultural workers.