It is pretty doubtful how long the power plants can be kept in operation without the workers

Union spokesman

On Wednesday, Kepco said it would sack all striking workers unless they returned to work by Monday.

But unions dismissed the threat as "reckless judgement" saying it was a gamble that would not pay off.

"It is pretty doubtful how long the power plants can be kept in operation without the workers. Then, the government should take the responsibility," said union spokesman Lee Byung-chul.

About 30 union leaders, including union chief Lee Ho-dong, have started an indefinite hunger strike at their refuge at Myongdong Cathedral in central Seoul. Several of them shaved their heads.

Limited impact

Kepco has turned to replacement workers and is training soldiers to relieve non-union workers who have kept electricity flowing.

So far, the impact of the strike has been limited because most power facilities are automated and being maintained by non-union workers.

Non-union staff make up a third of the total 8,400-strong workforce at the affected 31 power stations.

The planned asset sale is a key policy aim for President Kim Dae-jung's government in a presidential election year.