Some of South Korea's biggest employers have been paralysed by strikes, as 120,000 workers protest against working conditions ahead of next month's presidential election.

The financial markets are immune to this kind of action

Kim Young-ho of Daewoo Securities

Members of the Korea Confederation of Trade Unions (KCTU) downed tools at 0400 GMT, amid fears that employers may cut wages.

Worst-hit were big industrial firms, notably Hyundai Motor, Kia Motors and Ssangyong Motor, and KCTU officials said the action could spread in the next few days.

Tuesday's walkouts represent an escalation of a small strike by civil servants on Monday, which was sparked by government proposals to shorten the working week.

Analysts are predicting a wave of labour unrest in the weeks leading up to election on 19 December.

Industrial revolution

Hyundai, Korea's biggest car maker, said production of more than 10,000 vehicles had been lost, worth about 150bn won (�79m; $123m).

The news will further depress Korea's industrial output, which has stagnated in recent months.

Markets remained unfazed, however, ending the day down only slightly - and that only because investors had been cashing-in on a strong few days' trading.

"Labour unions always want to take advantage of this timing to call public attention to their demand, whether it's accepted or not," said Kim Young-ho of Daewoo Securities.

"The financial markets are immune to this kind of action."

Less work, less pay

Plans to cut the working week, announced by the government, may appear beneficial for workers, many of whom would no longer have to work Saturday mornings.

But the KCTU said overall workers incomes may fall and the government also wanted to cut the number of public holidays.

The parliamentary committee on labour is meeting this week to discuss the proposals to cut the working week by four hours to 40 hours.

The measure requires further parliamentary approval before it becomes law, however.