South Korea's two top presidential hopefuls kicked off 22 days of campaigning Tuesday for the crucial December election as polls predict an increasingly tight race.

The ruling Saenuri Party's Park Geun-hye, who is looking to become the first female leader of the country and extend the conservative rule for another five years, began campaigning with a stop at the National Cemetery in Seoul.

"(The election) will be the final journey of my political career of 15 years," Park told reporters at the cemetery where her father, military strongman Park Chung-hee, is buried.

The legacy of the senior Park's 18-year rule is subject to partisan dispute, with supporters lauding him for modernizing the country while critics pointing to human rights abuses.

Park, who acted as the de facto first lady to her father after her mother was assassinated, remains popular among older voters nostalgic for the rapid economic growth under the authoritarian rule.

The 60-year-old political veteran is an anathema, however, to former democracy activists such as Moon Jae-in, the presidential candidate for the main opposition Democratic United Party.

Moon, who was once jailed for protesting against the late dictator, flew to the conservative stronghold of Busan where he earned his first parliamentary seat earlier this year.

The 59-year-old former human rights lawyer, who also served as chief of staff to late President Roh Moo-hyun, has said his campaign represents new political voices disempowering the entrenched interests.

"This election is a contest between a society dominated by vested interests and a just society that puts human dignity before everything else," Moon told supporters during a campaign rally in Busan.

Latest polls show a tight race between the two rivals, with a survey of 1,500 people by ratings agency Realmeter putting Park at 45.4 percent compared to Moon at 43.8 percent.

The two candidates are vying to win over swing voters and former supporters of Ahn Cheol-soo, an independent who abruptly withdrew from the race last week to endorse Moon as a sole candidate on the liberal ticket.

Ahn, who was widely popular among the centrists and those disenchanted with the political establishment, was engaged in short-lived talks with Moon over merging their campaigns.

Analyses vary as to who would manage to absorb the majority of Ahn's supporters, but observers agree swing voters hold a key to the fate of the Dec. 19 election.

Incumbent President Lee Myung-bak, who defeated Park in the Saenuri Party's 2007 presidential primary, is constitutionally barred from seeking re-election.