Unionised workers at the South Korean unit of General Motors and a separate company that assembles its cars will vote over the next two days on a 15% wage increase agreement, the GM unit said on Tuesday, according to Reuters.

GM Daewoo Automotive and Technology Co said results of the vote by about 8,300 members of the union, which represents workers at both the company and Daewoo Incheon Motor Co, were expected to be released late on Thursday.

A GM-DATCO spokesman told Reuters labour and management negotiators had agreed to raise the basic monthly pay by 14.8%, or 145,022 won ($US123.40).

He said figures on the total wage amount were not available. Car workers in South Korea receive a big amount from various allowances, including overtime pay, in addition to basic pay, Reuters noted.

The news agency said agreement came after Hyundai Motor agreed last month on an 8.6% wage hike plus other benefits.