The government said Wednesday its key gauge of the nation's economic activity topped the boom-or-bust line of 50 percent in January for the second consecutive month.

The index of coincident indicators, which is designed to measure the current state of the economy, stood at 71.4 percent after a reading of 80 percent in December, the Cabinet Office said in a preliminary report.

A reading above 50 percent is considered to indicate expansion, while a figure below 50 percent indicates contraction.

The figures come as uncertainty over the course of the economy is growing in the wake of a string of dismal economic reports.

A Cabinet Office official said an analysis of the index does not show any immediate need for the government to change its view that the economy remains on course to recovery.

"But the index could slip below 50 percent in the months ahead as recent production-related data pointed to rising uncertainty," the official said. "We need to monitor the economic situation more closely."

The Cabinet Office also said the index of leading economic indicators, a measure of economic growth six to nine months down the road, stood at 57.1 percent in January, above 50 percent for the first time in three months.

The index of leading indicators, a measure of economic growth six to nine months ahead, rose above 50 percent for the first time in three months to 57.1 percent. The index stood at 50 percent in December.

The index of lagging indicators, which reflects activity in the recent past, stood at 50 percent, following a reading of 57.1 percent in December.

The diffusion indexes of the coincident, leading and lagging indicators compare the current levels of various economic indicators with their levels three months earlier.

Among the already available coincident index components for January, large-lot electricity consumption, investment goods shipments, department store sales, wholesaler sales and the ratio of job offers to job seekers showed positive readings.