Car sales by South Korean automakers fell sharply last month from a year earlier amid labor-management wage disputes and people taking time off for summer vacation, industrywide data showed Monday.

The combined sales of five local car manufacturers reached 638,372 vehicles in August, down 7.3 percent from 688,708 vehicles sold a year ago. The total excludes complete knockdown kits shipped abroad for assembly. 

Carmakers said labor strife, including partial walkouts and overtime work boycotts, hurt production and sales. Of the five original equipment manufacturers, only GM Korea Co. and Ssangyong Motor Co., reached agreements on this year's wage and collective bargaining negotiations as of last month.

Sales figures showed all carmakers backtracking on sales in the one-month period compared to the year before.

Hyundai Motor Co. and Kia Motors Corp., the country's two largest carmakers, sold 357,698 and 217,438 units, each, representing a decline of 5.9 percent and 3 percent from August 2013. The two are flagship companies of Hyundai Motor Group, the world's fifth-largest automotive conglomerate.

GM Korea, the South Korean unit of U.S. automaker General Motors Co., reported sales hitting 43,018, an on-year plunge of 30.4 percent, while SUV maker Ssangyong said it sold 9,659 cars, representing a 16.8 percent drop from the year before.

Renault Samsung Motors Co., the local unit of French automaker Renault S.A., said sales were off by 2.3 percent overall to 10,559 units.

On the domestic front, only Hyundai Motor posted a modest gain of 1 percent on-year, with others giving up ground.

Last month's sales reached 105,983 units, down more than 3.9 percent from 110,338.

"Walkouts lasting several hours triggered by the lack of headway in wage talks effectively hurt sales, along with many workers and consumers taking time off for summer vacation," a source at Hyundai Motor said.

He said in the case of Hyundai, overseas output, unaffected by labor disputes, prevented sales numbers from falling further. This view was echoed by its corporate cousin, Kia.

Hyundai said sales of its steady sellers such as its Avante compact, the all-new Sonata midsize sedan and the 2015 Genesis did relatively well in the home market. The Avante was the bestselling car in South Korea last month with 8,194 units sold.

Sedan sales were only down 1.1 percent on-year, with SUVs such as the Sante Fe and Tucson giving up a modest 2.2 percent.

Kia said sales of its Carnival minivan reached a healthy 4,841 units, with 9,000 still on the waiting list. It said sales of its K3, Morning and Sportage R helped numbers.

GM and Ssangyong said their Malibu and Korando Sports models did better last month vis-a-vis August 2013, with RSM's sales being helped by strong demand for its QM5 crossover that was given a makeover in recent months.

In regards to exports and overseas sales, only RSM said its numbers moved up 1.8 percent, with the rest giving up ground.

The five OEMs sold 532,389 vehicles abroad, down 7.9 percent from 578,370 units sold a year earlier.

Hyundai and Kia sales stood at 309,555 and 181,435 vehicles, respectively, compared to 332,605 and 185,229 units.

RSM's overseas sales moved up to 5,818 from 5,717, while GM Korea and Ssangyong announced sales fell 35.7 percent and 30.2 percent.

"Besides the strife, the drop-off in demand for cars in the emerging markets affected shipments abroad, with unfavorable foreign exchange rates hurting the competitiveness of local carmakers compared to main rivals that include Japanese carmakers," said an industry source.

GM Korea said midsize cars did well abroad, with Ssangyong reporting a slight improvement in sales of its new Rodius SUV. RSM said it sold 4,316 QM5 crossovers, up 24.8 percent on-year.

For the first eight months of this year, sales by local carmakers moved up 2.9 percent to 5,864,988. Only GM Korea reported selling less cars compared to last year.

Such gains extended to domestic sales, which moved up 3.8 percent on-year to 942,729 units from 908,115, with overseas sales gaining 2.79 percent.

In the January-August period, South Korean OEMs sold 4,922,259 cars in foreign markets, up from 4,788,653 units in 2013, the latest data showed. (Yonhap)