South Korea's conservatives dropped their presidential candidate on Saturday and reopened the nomination process, after the former prime minister decided to join the party to challenge the liberal frontrunner in an election just four weeks away.

South Korea’s embattled conservative party has canceled then reinstated the presidential candidacy of Kim Moon Soo within hours, after a failed attempt to replace him with former Prime Minister Han Duck-soo.

South Korea's People Power Party registered former labour minister Kim Moon-soo as its official presidential candidate on Sunday, a day after it attempted to cancel his candidacy.