South Korea's presidential race practically kicked off as registration began Monday for presidential hopefuls looking to replace the outgoing conservative leader, the National Election Commission here said.

Gyeonggi Province Governor Kim Moon-soo was the first to announce his candidacy for the ruling Saenuri Party's nomination, demanding the party adopt a new primary system open to the general public.

Chung Mong-joon, a business mogul, and Lee Jae-oh, a confidant to President Lee Myung-bak, are among the conservative heavyweights expected to soon announce their bids.

Leading the opinion polls is the party's interim chairwoman Park Geun-hye, who is credited with salvaging the scandal-ridden party and leading it to an upset victory in general elections earlier this month.

Moon Jae-in of the main opposition Democratic United Party is considered one of her more potent rivals, as polls suggest the rising popularity of the former chief of staff to late former President Roh Moo-hyun.

Software guru Ahn Cheol-soo, popular among the moderates and independents, is also considered a strong presidential contender.

The eight-month race will end on Dec. 19.