South Korea's transportation minister on Monday vowed stern measures against what he called an illegal strike by unionized cargo truck drivers while pledging to take available means to minimize the fallout on the local economy.

The warning came hours after some 7,000 truckers began staging a walkout while demanding the withdrawal of a recent government plan on modernizing the country's shipping industry.

Transport Minister Kang Ho-in asserted that the demand for the withdrawal of the government plan was only an excuse, saying the truckers' union had always taken part in the process of mapping out the plan all along the way.

"In addition, staging a walkout is an act of betrayal that ignores the efforts and sacrifice of many working day and night for this country and its economy," the minister said in a public address from his ministry in Sejong, 120 kilometers south of Seoul.

"Therefore, the government will sternly deal with this unjustified strike by the union of truck drivers in accordance with the law and principle," he said, according to a copy of his speech released by the Ministry of Land, Infrastructure and Transport.

The government's rather quick warning came as the truckers' strike happens during a prolonged walkout by unionized railroad and subway workers, further crippling the country's shipping network.

As of Monday, 7,390 or 40.3 percent of 18,351 unionized railroad and subway workers were taking part in the strike launched two weeks earlier, the ministry said earlier.

Since the start of the walkout by railway workers, the operation of cargo trains has been reduced to nearly half of the usual level, forcing local firms to depend on cargo trucks to haul their export and import shipments to and from the country's major seaports.

The government estimates cargo containers shipped by trucks may drop by as much as 32 percent from the usual level with some 7,000 unionized truckers taking part in the strike.

"The government will do its utmost to minimize any damage from the collective action by mobilizing all available means," Kang said.

Such government efforts will include an emergency injection of some 100 military cargo trucks and drivers along with additional resources and temporary workers to boost the operation of cargo trains.

Kang also said those taking part in the strike by truckers' union will be disqualified for government subsidies on fuel for up to six months.

"Lastly, I once again urge the truckers' union to immediately end its strike that will have a serious negative impact on the national economy," he said. (Yonhap)