South Korea's economy continued to slow down for four straight months on uncertainties at home and abroad, a state-run think tank said Tuesday.

The Korea Development Institute (KDI) said in its monthly report on economic conditions that the trend of economic slump continued in terms of both production and demand, keeping such assessment since November last year.

In the production front, output in the manufacturing and services sectors showed a low growth rate, while slowdown in the construction sector was seen, according to the KDI report.

From the demand side, both domestic demand and export weakened in recent months, the report said.

Retail sales gained 3 percent in December from a month earlier, staying below last year's monthly average growth rate of 4.2 percent.

Inventory among manufacturers kept rising from 106.9 percent in October to 111.7 percent in November and 116 percent in December, respectively.

Facility investment dropped 14.5 percent in December and 9.3 percent in November each compared with the same months of last year, after growing 10 percent in October.

Export, which accounts for about half of the economy, reduced for two months to January on soft demand for chips and oil products.

The government set the country's growth forecast for this year at a range of 2.6-2.7 percent, higher than an average outlook of 2.5 percent from the survey of 21 experts conducted by the KDI.