SEOUL - SOUTH Korean police tried to clear the remnants of a massive protest that clogged central Seoul on Wednesday as the president looked to embrace a political rival to bolster his troubled government.

The protests against President Lee Myung Bak, in office barely three months, were sparked by public outcry over a deal to widen the beef market to United States imports and have cast a darkening cloud over his plans for sweeping, pro-business reforms.

In what was described by local media as the biggest demonstration in the capital in about 20 years, mothers with toddlers, college students, office workers and radical labour activists shouted 'Lee Myung-bak Out' as they marched with candles through the streets on Tuesday night.

Mr Lee's can-do image, first earned as CEO of Hyundai Construction, helped him win the presidential race.

But this has now become his greatest liability. The public sees him as too focused on pushing through his own plans and unconcerned about their needs, analysts have said.

Mr Lee looks ready to call Ms Park Geun Hye, his main rival for control of the conservative Grand National Party (GNP), into his government as prime minister, the Chosun Ilbo newspaper said.

The April beef deal with the United States was meant to help a separate bilateral free-trade accord that United States congressional leaders threatened to block unless South Korea opened up its market to beef imports.

But widespread concern over mad-cow disease in US beef quickly turned the issue into a lightning rod for a broad range of grievances against Mr Lee's government.

His Cabinet offered to resign on Tuesday to take responsibility for the fallout from the beef deal.

Analysts said Mr Lee expects Ms Park, who once ran the GNP and is also the daughter of an assassinated South Korean president, to unite the faction-ridden party and have her experienced political hand guide his reforms through parliament.

'The Park Geun Hye card is an essential one to play now because nobody is trying to listen to his voice any more,' said Mr Choi Jin, the chief of the Institute for Presidential Leadership.

Mr Lee stormed to a landslide victory in a December presidential election with pledges to rebuild the world's 13th largest economy but now has a support rate of under 20 per cent.

Local media said Mr Lee would start a government reshuffle this week and speculated he would ditch his farm, health and education ministers, along with several aides, and possibly the foreign and finance ministers.

The growing political storm has all but blocked the government's plans for major economic reform, including tax cuts, privatisation of major state-run firms and banks and efforts to make the country more accessible to foreign investment.

The new conservative-dominated Parliament has been unable to sit because the opposition has boycotted its opening. -- REUTERS