Automakers are struggling with lackluster sales amid a drawn-out economic slowdown.

Korea's five automakers -- Hyundai and affiliate Kia, GM Korea, Renault Samsung and Ssangyong -- saw their sales drop last month. Their combined sales fell by 4 percent on-year to 703,777 units in October.

Hyundai and Kia saw their domestic and overseas sales plummet by 2.5 percent and 0.8 percent overall, bucking the trend that had been seen until the previous month of small increases of 1 to 2 percent.

"We are struggling with weak demand in the U.S. and China. Besides that, the release of the new Grandeur sedan led to a significant drop in sales of existing models," said a Hyundai spokesman.

The situation is even worse for the three other automakers. GM Korea saw its sales fall by 25.5 percent to 30,158 units on-year, Renault Samsung by 20.4 percent to 14,826 units, and Ssangyong by 24.1 percent to 10,135 units.

An industry insider said, "With exports declining, they have no plans to release new cars, so it is unlikely they will see a recovery in sales anytime soon."