South Korean consumer sentiment declined to a five-month low in September as private spending remained subdued amid lingering economic uncertainty, the central bank said Thursday.

The consumer sentiment index (CSI) -- a gauge of consumers' overall economic outlook, living conditions and future spending -- came in at 102 for September, down from 105 tallied in the previous month, according to the Bank of Korea (BOK).

The index stayed unchanged at 105 for the third straight month in August, the highest level since May 2012.

A reading above 100 means that optimists outnumber pessimists.

The survey, based on a poll of 2,014 households nationwide, was conducted from Sept. 9-17.

The BOK said that consumers' outlook for spending turned worse, mainly driven by a hike in housing expenses, in an indication that weak domestic demand is dragging on the local economy.

The Korean economy grew 1.1 percent on-quarter in the April-June period, the fastest gain in over two years. But it also faces downside risks such as uncertainty over U.S. stimulus reduction and emerging market turmoil.

The index measuring the economic outlook came in at 97 for September, up from 93 recorded in August. But the index gauging the current economic assessment reached 77 for September, compared with 81 in the previous month, the BOK noted. (Yonhap News)