Google has disabled user uploads and comments on the Korean version of its YouTube video portal in reaction to a new law that requires the real name of a contributor be listed along with each contribution they make.

The rules, part of a Cyber Defamation Law, came into effect on April 1 for all sites with over 100,000 unique visitors per day. It requires that users provide their real name and national ID card number.

In response to the requirements Google has stopped users from uploading via its Korean portal rather than start a new registration system.

"We have a bias in favor of freedom of expression and are committed to openness," said Lucinda Barlow, a spokeswoman for YouTube in Asia. "It's very important that if users want to be anonymous that they have that chance."

But while the move obeys the letter of the law it skirts around the spirit of it by allowing users based in South Korea to continue uploading and commenting on YouTube by switching their preference setting to a country other than Korea.

YouTube noted this workaround on its Korean Web site, and any videos and comments contributed this way will still be seen by Internet users in the country.

The decision was taken after close consultation and debate between Google Korea and its headquarters, Barlow said.

The new law was rushed into force after the suicide of a popular actress in October focused attention on the problem of online bullying in the highly-connected country.

Choi Jin Sil was apparently driven to suicide after a series of online rumors had her pressuring a fellow actor to repay a loan she had made to him. The actor, Ahn Jae Hwan, had killed himself a month earlier.

The suicide was the latest in a string of so-called cyber-bullying incidents in the country and helped generate support for the stricter law.

The first high-profile case occurred in 2005 and involved a woman who quickly became known as "dog poop girl." After her dog defecated on the Seoul subway and she failed to clean it up, a fellow traveller posted a picture of her online with an account of the incident. The story spread fast and within days a campaign had identified her, where she lived, and the university she attended. In the end, she reportedly dropped out of school and fled her home because of the controversy.

Already many major Korean portals and Web sites require users to provide their national ID card number when registering accounts but Google, which has a much smaller profile in South Korea than it enjoys in the west, does not ask for this information so the law would have also required it to build a new verification system.