The other top candidate in opinion polls is Lee Hoi-chang, who heads the main opposition party.

FORBES: Would-be captain of Team Korea

Not surprisingly, Lee Hoi Chang, the candidate for the ruling New Korea Party (NKP), has little good to say about the set-up.

CNN: Alliances and Defections

Heading the ticket as presidential candidate is South Korea's "Mr. Clean, " the respected, incorruptible, maybe even a bit naive Lee Hoi Chang, a former judge.

CNN: Change at the Top

But the president, limited to one term, probably has less to fear from his predecessor in the Blue House than does the leader of the opposition, Lee Hoi Chang.

CNN: THE RETURN OF THE THREE KIMS

Five years later, Mr Roh surprised perhaps even himself in the race to be president by defeating the favoured establishment candidate, a former Supreme Court chief justice, Lee Hoi-chong.

ECONOMIST: South Korean politics

Kim bowed to pressure - including a poll-boycott threat - from opposition leader Lee Hoi Chang to keep the single-member constituencies, even though that will help the opposition in Assembly elections next April.

CNN: Of 'Fur-gate' and Other Fights