Hyundai Motor's labour unions are stepping up strike action follow their failure to reach an agreement with management over renumeration, according to local reports.

The company rejected union demands for a KRW154,883 (US$142) rise in monthly basic wages for next year and combined bonuses equivalent to 30% of last year's net profit of KRW5.72 trillion.

Management's latest offer was for a KRW42,879 wage increase, annual bonuses equivalent to 250% of basic pay and an additional payment of KRW1.5m. It said the company faces "difficult times" at present, including weak vehicle demand in key overseas markets

Unions said their members would step up industrial action next week, after failing to reach an agreement with management over the last eight months. 

Until now, unionised workers have staged walk outs at the company's Ulsan plant, halting three assembly lines for four to six hours daily four days per week. This has reduced output by 43,000 vehicles so far this year. 

Next week stoppages will be stepped up to six to eight hours per day, five days per week.