A key gauge of the current state of the economy fell below the boom-or-bust line of 50 percent in April for the first time in four months, due in part to slowing production.
The index of coincident economic indicators came to 16.7 percent for the reporting month, down sharply from a revised 90 percent in March, the Cabinet Office's Economic and Social Research Institute said Thursday in a preliminary report.
Yoshihiko Senoo, director of the institute's business statistics department, said that because the drop was still a one-month phenomenon, the government is maintaining its view that the coincident index is moving on a "roughly flat" trend.
"But production-related statistics point to uncertainties, and we believe we must observe the movement of the coincident index carefully," Senoo said.
A particularly worrying factor was the unclear prospect for exports due to sagging demand from the United States and the rest of Asia, which has been hit by severe acute respiratory syndrome, Senoo said.
A reading above 50 percent is considered a sign of economic expansion, while a figure below that is seen as a sign of contraction.
The index of leading indicators, measuring economic moves about six months down the road, came to 33.3 percent, up from a revised 27.3 percent in March. The index remained below the 50 percent line for the second month in a row.
It was the first time since December 2001 that the coincident index and leading index were both below the bust line.
The index of lagging indicators, designed to gauge economic performance in the recent past, was 75 percent, up from a revised 50 percent in March.
The diffusion indexes compare the current levels of various economic data with their levels three months earlier.