Hyundai Motor Co's total sales fell for the first time in more than three years in August, hurt by a slew of partial strikes at South Korean factories that hit domestic sales hard.

Workers staged the partial strikes in July and August, their first walkout in four years and the South Korean automaker's second-costliest strike, as annual wage talks stalled over pay, a new shift scheme and other factors.

Hyundai and its union leaders last week reached a tentative wage deal, which if approved in a Monday vote will allow the carmaker to avert further walkouts.

Results of the vote are expected after midnight, a union spokesman said.

Hyundai, the world's fifth largest carmaker along with affiliate  kia motors said it sold 293,924 vehicles globally last month, down 4.6 per cent from a year earlier, the first fall since May 2009 in the wake of the global financial crisis.

Hyundai's domestic shipments slid 30 per cent, while its overseas sales inched up 0.4 per cent.