Two South Korean presidential hopefuls have taken part in a live television debate to help determine who will stand against the conservative frontrunner.

The two men, former human rights lawyer Roh Moo-Hyun, and millionaire football chief Chung Mong-joon, have agreed to join forces to defeat Lee Hoi-chang, who has been consistently leading opinion polls.

A poll published on Tuesday indicated that either Mr Chung or Mr Roh could win if one stepped aside as a candidate.

During the debate Mr Roh kept Mr Chung on the defensive but both candidates appeared to acquit themselves well, AFP news agency reported.

The presidential election will be held on 19 December to find a successor to the incumbent leader Kim Dae-jung, who must stand down after a five-year term.

'Chalk and cheese'

The BBC's correspondent in Seoul, Caroline Gluck, says the two reformist candidates appear worlds apart in terms of background and political ideology

But now only one of them will be fielded in the election. Who that is will be determined by the outcome of opinion polls over the weekend, following their primetime debate on Friday.

Conservative contender Lee Hoi-chang

The men have promised that the loser will campaign for the victor against Mr Lee.

Mr Roh, the candidate for the ruling Millennium Democratic Party, and Mr Chung, who has recently formed the National Alliance 21, agreed to merge their campaigns last week.

But since then the agreement has hit several stumbling blocks. Mr Roh said on Friday that all argument had now been resolved.

Election issues

Among the issues at stake in the election is South Korea's 'sunshine policy' of engaging with the reclusive North.

The policy has been put under severe strain by Pyongyang's alleged admission that it has a nuclear weapons programme.

Although all candidates have called on North Korea to scrap its nuclear programme, Mr Lee has called for financial aid to Pyongyang to be halted until its arms ambitions can be clarified.

North Korea has made it clear it does not want Mr Lee to win.

"Lee is desperately tightening the bridles of the nuclear war chariot, while trumpeting about co-operation for the implementation of the US war policy," the North's party daily Rodong Sinmun said on Tuesday.