Workers at GM Korea Co. will stage a partial strike Tuesday to demand higher wages as the company has not offered any satisfactory terms in this year's wage talks, the union said.

GM Korea union said its day-shift workers in the company's plant in Bupyeong, about 30 kilometers west of Seoul, will carry out a four-hour strike and night-shift workers will also walkout for four hours.

"The planned strikes are a normal part of wage negotiations," union spokesman Dang Sung-geun said by phone. 

The South Korean unit of General Motors Co. and its union have held 18 rounds of wage talks since July 24 but have yet to reach an agreement.

The union is demanding the company raise workers' monthly basic wages by 154,883 won ($133) and offer 500 percent of the basic wage in bonuses -- demands that GM Korea deems excessive.

GM Korea offered an increase of 50,000 won in basic monthly salary and 4 million won in bonuses per worker.

GM, the Detroit-based parent company, is in the process of carrying out worldwide restructuring, and the Korean unit has consistently posted poor performances in recent years.

It posted net losses in the past three years -- 350 billion won in 2014, 986.8 billion won in 2015 and 631.4 billion won in 2016, due mainly to slowing global demand.

Other demands include the establishment of the so-called 8+8 shift system in which night-duty workers finish their day at 12:40 a.m., not 1:40 a.m. under the existing 8+9 system.

Last year, the company agreed to start the 8+8 system on June 1 this year, but the union and management held only one meeting to discuss follow-up steps in regards to the working hours change, Dang said.

The union wants to discuss the issue during this year's wage negotiations in order to introduce the system as agreed upon, he said. (Yonhap)