(Adds background on overall labour situation)
By Jean Yoon
SEOUL, Aug 25 (Reuters) - A strike by thousands of South Korean truck drivers hit freight flows at the country's main ports on Monday, costing $338 million in delayed shipments, affecting top exporters such as Samsung Electronics.
Labour unrest in South Korea, which has a reputation for union militancy, has come under the spotlight this year as the new centre-left government of President Roh Moo-hyun, a former labour lawyer, has been perceived as being soft on unions.
Industrial action over wages and union demands for greater say in management have become key hurdles in luring foreign investment, analysts say.
About 30,000 drivers stopped work for a fifth day demanding more talks to end their dispute, while employers have threatened legal action over a strike that has endangered the export-dependent economy.
South Korea's leading groups of employers, including the Federation of Korean Industries (FKI) and the Korea Employers' Federation, have urged a tough stand to prevent the walkout from setting a negative example.
"We estimate several hundred million won worth of financial damage as a result of production delays in the manufacturing sector and disruption in export and import transportation following the strike," the FKI said in a statement.
The drivers' action follows nearly seven weeks of strikes at Hyundai Motor Co , which cost the nation's top car maker $1.2 billion in lost output before the dispute was settled.
"We are having trouble delivering some 30 percent of home appliances from our Kwangju plant," said Yim Juk-suk, a spokesman for Samsung Electronics Co , Asia's most valuable technology firm.
The Kwangju factory in the southwest of the country produces mainly bulky refrigerators and vacuum cleaners. Home appliances account for 10 percent of its total sales. Rival LG Electronics Inc , the world's biggest producer of air conditioners, said it was also affected.
KIA STRIKE ENDS
The strike by the drivers, who have been pressing for higher cargo fees and recognition of their union, has been labelled illegal by authorities, but there had been no attempt to stop it.
Talks to end the dispute broke down on Friday, but the drivers said they wanted more negotiations. The government vowed to take action to minimise the economic impact of the stoppage.
Container cargo transport has fallen by about 40 percent at the port of Pusan, about 400 km (250 miles) southeast of the capital Seoul, which handles 80 percent of South Korea's container cargo, the government said.
South Korea's top oil refiner SK Corp said it was concerned about a prolonged strike, as the port in Pusan handles about a third of its total petroleum exports. Smaller steel, tyre, cement and textile firms have also reported disruption.
Separately, unionised workers at Kia Motors Corp , South Korea's second-largest auto maker, have returned to work, ahead of talks on wages with management later on Monday.
The 23,500-strong union had temporarily ended around 20 days of full and partial strikes, which has cost Kia about 530 billion won ($450.9 million) in lost output. But the union may resume industrial action, depending on the result of their talks.
The South Korean government has prevented truck drivers from forming unions, arguing they are self-employed. But the drivers say since they are hired by transport companies they should be allowed to form a union.
In May, truck drivers ended a week-long strike that choked the movement of freight through Pusan after the government buckled to union demands.
($1=1175.5 Won)
(Additional reporting by Park Sung-woo and Judy Lee)