Workers staged four-hour walkouts at two plants of South Korea's Ssangyong Motor Co today Wednesday to protest against the sale of a controlling stake in the company by its creditors to the Chinese government-controlled China National Bluestar Corp.

An all-out strike has been threatened for January 27.

Blue Star has said it will invest over $1 billion by in SsangYong over the next six years. Though it is described as a chemicals company, Blue Star already operates five automotive assembly plants, and took control of several Chinese military vehicle production sites two years ago.

It also has joint ventures with two South Korean auto parts makers and supplies parts to a Hyundai assembly plant in China. South Korean unions are reportedly chiefly concerned at the impact of large wage differentials between Korea and China. The UK concessionaire for SsangYong, currently building a stand-alone franchise network, was appointed by SsangYong under the overall control of its creditor banks.