South Korean construction workers went on strike on Monday to press for cheaper fuel and higher pay, joining thousands of truckers who walked off the job last week, crippling the export-dependent country's ports.
More than 18,000 operators of construction machinery are also angry over the policies of President Lee Myung-bak, who came to office in a landslide victory but has seen his support plummet after an unpopular deal to resume imports of U.S. beef.
Adding to his woes, the militant Korean Confederation of Trade Unions (KCTU), which opposes Lee's privatization and pension plans, is set to announce the results of its all-but-certain vote to go on strike later on Monday.
The strikes have so far cost the country $3.5 billion, according to the commerce ministry.
They come as Lee grapples with massive street protests that initially called for the repeal of the U.S. beef deal but broadened to attack a range of his policies.
The demonstrations, which have hit a lull in recent days, could reignite after the trade ministry said on Monday talks between South Korean officials and the United States to address public health concerns over the beef deal had broken down.
Lee's entire cabinet and all his top aides at the presidential office have offered to resign, and Lee is expected to replace a sizable number of them.
Unionised truckers represent only a small portion of the country's drivers but play a key role in moving goods in and out of ports. About 14,000 walked off the job on Friday after talks on higher pay and cheaper diesel broke down.
Movement of cargo containers through the country's biggest port of Busan picked up slightly due as replacement drivers were brought in, but remained precariously slow, with the port's container yard filled to 85 percent capacity, a port authority official said by telephone.
Lee has pledged to boost Asia's fourth-largest economy by 6 percent this year, which economists say is overly ambitious in the face of record high oil prices and a global slowdown.
Speaking to finance ministers from Asia and Europe on Monday, Lee warned the world economy was facing its gravest crisis in more than three decades and called for tighter coordination among regional organizations to tackle the problem.