Major parties have been launching primary races to pick their standard bearer for the December presidential election with Saenuri Party’s Park Geun-hye unchallenged as a poll leader.

The ruling party kicked off its month-long in-house election campaign on Saturday contested by five candidates. The former party chairwoman is currently the unrivalled frontrunner.

Eight candidates will officially begin the competition this week to represent the main opposition Democratic United Party in the presidential election. They are striving to gain an upper hand over powerful potential candidate Ahn Cheol-soo who has no party affiliation.

The Saenuri’s four underdogs ― Gyeonggi Governor Kim Moon-soo, former South Gyeongsang Governor Kim Tae-ho, former presidential chief of staff Yim Tae-hee and former Incheon Mayor Ahn Sang-soo ― on Sunday issued a joint statement calling for changes to the party’s debate rules.

According to the party’s primary management committee, the five aspirants are to participate in 10 joint public address sessions and nine debates including six televised ones.

Each session is to be held with a specific topic, including one requesting the candidates to compliment one of his or her rivals.

“The candidates should be able to freely select their topics and questions in order to bring out one another’s policies,” Yim said in the joint statement.

“Unless our demands are accepted, we shall boycott the joint sessions and hold an official press conference to censure the party’s unreasonable rules.”

The four also suggested that the rule was an attempt to prevent possible criticism against frontrunner Park.

They also refused to participate in the video speech slated for July 27 in Busan, citing a lack of time and budget.

“The party is making unilateral decisions on the primary rules, without communicating with the candidates,” said Ahn.

Amid the ongoing disputes over the debate rules, the candidates also stressed their respective election campaigns in an attempt to differentiate themselves from Park.

Former presidential official Yim’s strategy is to underline his 20-year experience in party politics and government administration.

Former South Gyeongsang governor Kim, who is the youngest of the five, prioritized his young and energetic image.

The right-wing party is scheduled to select its final presidential representative in a national convention on Aug. 20, according to officials.

The DUP, on the other hand, is expecting a more complicated race as its eight registered candidates also must consider professor Ahn Cheol-soo, who has not yet announced his presidential bid.

The liberal party will first hold a preliminary race this week to sort out five finalists through public polls conducted on party members and ordinary citizens. The final candidate is to be selected in late September, according to the party’s election committee.

Among the in-party figures, Rep. Moon Jae-in, former aide to late President Roh Moo-hyun, currently takes the lead over the others such as former party chiefs Sohn Hak-kyu and Chung Sye-kyun, as well as former South Gyeongsang Governor Kim Doo-kwan.

Moon, however, is still rated behind the right-wing frontrunner Park and non-party hopeful Ahn, according to recent polls.

The Seoul National University professor once again drew the political spotlight by publishing his book “Thoughts of Ahn Cheol-soo” last week.

Though he refrained from confirming his final stance on the December election, many regarded his book as a preview of his upcoming candidacy announcement.

By Bae Hyun-jung (tellme@heraldcorp.com)