Weeks of street rallies, which have often turned violent, have shaken the government of newly elected President Lee Myung-bak.

Protest organisers, which include civic groups, religious leaders and a labour group said they expected hundreds of thousands to attend.

There were no major incidents of violence in the first few hours of the rally.

The protests began in early May by people worried about possible mad cow disease in US beef.

Rallies last weekend left hundreds of protesters and conscripted riot policemen injured, prompting religious leaders to join the rallies in the hopes of calming things down.


South Korean and US trade ambassadors reworked the beef deal in June, limiting trade in beef to cattle under 30 months of age, thought to pose a low risk for mad cow disease, and prohibits shipments of risky body parts.

US beef returned this week to store shelves in South Korea, five years after Seoul banned sales in 2003 due to an outbreak of mad cow disease in the United States.

Agencies