Korea’s downstream company LG-Caltex Oil Corp has given its striking workers until tomorrow to return to work tomorrow or face “severe action.”

Korea Herald reported that since July 19, more than 700 unionised workers have gone on strike at the oil refiner’s plant in Yeosu, 450 kilometers from Seoul, demanding a 10.5% pay raise and a shorter work week.

Authorities have declared the walkout illegal because the strike was launched during a government mediation period.

The work stoppage at the 650,000 barrels/day refinery has disrupted the supply of fuels to the Korea’s domestic market.

The company has not specified what action it might take against the striking workers.

The Korea Herald said that if plant operations are not normalised, the refinery could lose 40 billion won a day. (US$1=1,200 won). The refinery, which supplies about 30% of the nation’s oil needs, has been operating at 70% capacity since shortly after the strike began.

The report said that about 41% of LG-Caltex’s 2,700-strong work force belongs to the union. Of the striking members, 12.5% is back to work, and the company expects more to join them.

The union has failed to win popular support, with many Koreans criticising it for demanding higher salaries while the country is mired in a sluggish economy.

LG-Caltex is equally owned by LG Corp. and Caltex Corp., a unit of ChevronTexaco Corp.