UPDATE 1-Fuel runs short at S.Korean petrol stations as top union begins strike alongside truckers

(Changes dateline, updates with government estimates, comments from the trade union's rally)

By Ju-min Park and Heekyong Yang

UIWANG, South Korea, Dec 6 (Reuters) - A nationwide strike by South Korean truckers has led nearly 100 petrol stations across the country to run dry, government data show, and a national trade union launched a general strike on Tuesday in support of the drivers.

The truckers' strike over a minimum pay programme, which began on Nov. 24, has seen two negotiation sessions between the union and the government, but so far there has been no breakthrough.

The Korean Confederation of Trade Unions (KCTU) said it held rallies at 15 sites across the country, with about 25,000 unionised workers attending as part of its general strike.

As supplies of fuel and construction materials run low, the South Korean government has stepped up pressure to end the strike. Last week, the government issued a "start work" order to force 2,500 striking drivers in the cement industry back on the road.

President Yoon Suk-yeol on Sunday ordered preparations to expand that order to sectors such as oil refining and steelmaking, where additional economic damage is expected.

The anti-graft Korea Fair Trade Commission (KFTC) said it kicked off an investigation last week to investigate whether the truckers' union unfairly refused to work. The union is not cooperating with the probe, a KFTC official told Reuters on Tuesday.

The KCTU, an umbrella union under which the truckers' union falls, has called the President's "start work" order the equivalent of martial law and says the government should negotiate.

At one of its demonstrations near the Uiwang container depot, where striking truckers are camping out, KCTU chief Yang Kyung-soo said the truckers are on the "front lines" of protecting workers' lives and rights. Leaders of member unions made financial contributions to the ongoing strike by truckers.

Lee Bong-ju, head of the truckers' union, said unionised truckers would raise the level of their protest starting Wednesday, without elaborating.

As of Monday afternoon, nearly 100 petrol stations had run out of fuel. About 60% of them were in Seoul and Gyeonggi province, a densely populated region near the capital, according to Korea National Oil Corp data. That is up from the 21 petrol stations that the industry ministry had said were out of fuel on Nov. 29.

Amid soaring fuel costs, as many as 25,000 truckers are calling on the government to provide a permanent minimum-pay system known as the "Safe Freight Rate", which was introduced temporarily in 2020 for a small portion of more than 400,000 truckers.

In their second strike in less than six months, those truckers are fighting the bitter cold and the government's narrative that they are well paid "labour aristocracy".

Yoon has said the government will not give in to the union's demands and likened the strike to North Korea's nuclear threat. The government has said it would extend the current programme for three more years.

The impact of a general strike is unclear and depends on participation, said KCTU spokesperson Han Sang-jin.

Another KCTU official said some workers in the service and construction sectors had launched "solidarity strikes", but did not know how long they would continue.

"By being here, we are hoping to cheer up our truckers," Park Dae-ku, an unionised worker at a government-run science museum, told Reuters. Park took a few hours off to join the rally at Uiwang but is not planning to walk out of work.

The strikes have disrupted South Korea's supply chain, and cost the country 3.5 trillion won ($2.65 billion) in lost shipments over the first 12 days, the industry ministry said on Tuesday.

Losses are expected to have grown in several industries, but traffic at ports has improved slightly to 69% of its pre-strike average since the back-to-order was issued, according to the government. ($1 = 1,320.8200 won) (Reporting by Ju-min Park and Heekyong Yang; Editing by Gerry Doyle)