South Korean manufacturers' business sentiment will remain unchanged next month, though they expect an increase in domestic demand and exports, central bank data showed Tuesday.

The business survey index (BSI) of manufacturing firms came to 72 in December, unchanged from a month earlier, according to the Bank of Korea (BOK).

A reading above 100 means optimists outnumber pessimists, while a reading below the benchmark means the opposite.

An index measuring local firms' sentiments toward exports came to 87 for December, up from 82 for November.

A separate index for domestic sales stood at 83 for next month, up from 78 in November.

Still, local companies expected their profitability to slightly worsen next month, registering a BSI reading of 87 for December, down from 88 in November, according to the BOK.

The BSI of nonmanufacturing firms came to 72 in December, compared with 73 in November.

The monthly index is based on a survey of 2,789 companies throughout the country from Nov. 15 to 22. (Yonhap)