It's well after 8.00 pm in central Seoul's commercial district, but the lights are still burning brightly in many office towers.

A nine-to-five existence sounds humdrum in other countries, but for most South Korean office workers it's a distant dream. Even a normal working day lasts 10 hours...and then there's the overtime.

"I work overtime at least four days a week,1' said a 30-year-old who asked to be identified only by an alias, Lee.

His company, like most others, does not pay overtime to office workers. But staff still stay on for at least 30 minutes to one hour, and sometimes longer, after the official workday ends.

In a nation which worked itself out of acute postwar poverty into prosperity, some feel amoral compulsion to linger late. Others fear they will damage promotion prospects by leaving the office before the boss.

Whatever the reason, South Koreans work longer hours than any other member of the Organisation for Economic Cooperation and Development — an average 2,243 hours a year or 46.6 hours per week, according to 2009 OECD data.

This is 500 hours more a year than Japan and about 900 hours more than Germany.

However, the organisation's data on productivity in all sectors ranks Korea third from the bottom of 30 OECD countries.

The labour ministry says shorter hours could improve both lifestyles and productivity. But ingrained attitudes take time to change.

"Korea's economy still has potential to grow and Koreans have a strong ethnic characteristic to compete and to finish their jobs as soon as possible," Yang Yoon, a psychology professor at Ewha Womans University,

told AFP.

"With those two factors combined, it makes the so-called overworking culture exclusive to Korea."

"Working late is understandable. Much of the time, I stay late to finish my report or task of the day," said a 29-year-old electronics company employee, Shin. Like others, he asked to be identified only by his surname.

Sometimes, it's the company hierarchy — and a perception that overtime working is virtuous — which keeps lower-level employees sitting tight at their desks till late in the evening.

"The older generation, who worked through the boom time for the Korean economy, are simply so used to working overtime, like Japan in the 1970s," said professor Yang.

"It's hard to just walk out if the clock says I can go but my boss is still there," agreed Kim, 29.

"I once had a boss who would make me stay late by giving more work right before I go home or would simply ask me, 'Whyareyou leaving so early?'"

Lee said the "smothering" office atmosphere -- and a fear of damaging promotion prospects -- makes staffers linger at their desks.

The labour ministry in 2004 announced a 40-hour work-week policy for companies with more than 1,000 employees. It has since progressively extended this to smaller firms.

In December the ministry announced the policy would apply from July to companies with fewer than 20 employees. This is estimated to cover about 300,000 firms with about two million employees.

"Although Korea has the longest working hours in the OECD, if the policy is implemented, the quality of life and efficiency are expected to

improve," said ministry official Jo Won-Shik.

"Labour productivity usually is inversely proportional to working hours, so lower working hours are likely to mean higher productivity," Jo told AFP in a phone interview.

"Moreover, shorter working hours will increase leisure time, improving the quality of life."

It might even boost the nation's chronically low birthrate.

The health ministry in January 2010 announced it was turning off the lights in its offices at 7.30 pm once a month to encourage staff to go home early and make more babies.

Professor Yang is optimistic the workaholic culture will die out in time.

Jeon, a 25-year-old trading company staffer, said overtime was definitely not positive. "But I have work flooding in and it doesn't just go away.11