South Korea’s main opposition party presidential candidate Moon Jae-in called on his independent rival to talk on a strategy to garner the liberal vote and forestall a victory for Park Geun-hye of the centre-right New Frontier party.

Mr. Moon is set to negotiate with Ahn Chul-soo on a “united candidacy” ahead of the elections in December, which means one of the two contenders would have to drop out of the race and endorse the other. According to analysts, the liberal vote will divided if both men run for office, handing a sure victory for Ms. Park, who is already leading the polls.

“We should not delay the discussion on this any longer: it is time to start the dialogue on a united candidacy,” Mr. Moon’s spokesman, Woo Sang-ho, told reporters Tuesday. “I would like to officially ask Mr. Ahn how long he wants to postpone the discussion”.

Mr. Moon might promise to make Mr. Ahn his prime minister if he withdraw his candidacy, local media said.

The electoral battle has focused on “economic democratization” with all three candidates vowing to root out Korea’s chaebol, or business conglomerates, that have seemingly benefited from President Lee Myung-bak’s administration.