South Korean manufacturers' sentiment for business conditions weakened to the lowest level in 18 months amid lingering uncertainties, a poll showed Friday.

The business sentiment index, which measures the outlook of manufacturers on their business conditions for the coming month, came in at 73 for February compared with 77 in the previous month, according to the Bank of Korea. It is the lowest reading since August 2013.

In terms of seasonally adjusted figures, the monthly index also slumped to 74 from 80.

A reading below the benchmark 100 means that pessimists outnumber optimists. The index has been hovering below the threshold since July 2010 when it hit 100.

The central bank said that lingering uncertainties at home and abroad hurt sentiment.

"An increased number of manufacturers picked economic uncertainties and sluggish shipments as their grave concerns given the recent developments in the eurozone economy," said a bank official.

By sector, the index measuring large corporations' forecast slumped by five points to 80, while the index for small and medium enterprises slipped two points to 71.

The index measuring domestic-focused companies' outlook dipped by one point to 73, while the reading for exporters plunged by seven points to 74.

The outlook for February is based on a nationwide survey of 2,862 companies conducted from Jan. 16-23.

Last year, the South Korean economy, Asia's fourth-largest, grew 3.3 percent.

For the year, the central bank expects a 3.4-percent expansion, while the finance ministry puts its growth estimate at a higher 3.8 percent. (Yonhap)