South Korea's industrial output growth slowed in April due to sluggish production in chemicals, autos and audio & video equipment, a government report showed Tuesday.

Output in the mining, manufacturing and electricity & gas sectors expanded 6.9 percent in April from a year earlier owing to strong demand for semiconductors and components, Statistics Korea said in a monthly report.

It marked the 22nd straight month of on-year expansion since July 2009, but the growth has slowed since January last year when it peaked at a 36.9 percent year-on-year increase. The output growth posted 9.1 percent and 8.7 percent in February and March respectively.

From a month earlier, industrial output contracted 1.5 percent as underperformance in chemicals, autos and audio & video equipment outweighed solid demand for semiconductors and parts, according to the report.

Shipment in the mining firms and manufacturers rose 7.3 percent in April from a year earlier, but declined 1.7 percent from a month before. Inventory grew 8.9 percent year-on-year and 1.1 percent month-on-month each, the report showed.

Local manufacturers operated at an average capacity of 80.5 percent in April, down 2 percentage points from the previous month. The factory utilization rate stood at 81.7 percent a year ago.

The leading index of economic indicators, which gauges business activity eight to 15 months ahead, fell 0.3 percent from a month earlier. The coincident index, measuring current economic conditions, also decreased 0.2 percent last month, according to the report.

Production in the service industry grew 3.1 percent in April from the previous year due to upswings in financial, insurance, healthcare and social welfare sectors, the report said.

Retail sales posted a 5 percent on-year gain last month as brisk sales in durables and semi-durables outnumbered slowdown in non-durables such as car fuels. From a month earlier, retail sales contracted 1.1 percent last month.

Facility investment in April decreased 1.1 percent year-on-year and 5.7 percent month-on-month each due to declining investment in transportation equipment, the report said.

In April, the value of construction completed at constant prices fell 8.9 percent from a year earlier, with the value of construction orders received at current prices dropping 2.7 percent from the previous year.