The race to the presidency has turned into a mudslinging contest, with the two leading candidates appearing to focus mainly on dragging each other down with accusations.

The two-way race between Lee Jae-myung of the ruling party and his main opposition counterpart, Yoon Suk-yeol, has consisted largely of remarks questioning each other’s fitness for the chief post.

The main opposition People Power Party on Monday called on Lee to accept a special counsel probe concerning a controversial land development project in Seongnam, Gyeonggi Province, when he was mayor of the city in 2015.

Lee is dogged by suspicions of unlawfully favoring his aides for the project.

"Candidate Lee Jae-myung clearly voiced his intention to accept the special counsel inspection without conditions, but the Democratic Party really has no intention to accept that even though it said it would do so on the surface," People Power Party spokesperson Jeon Ju-hye said in a commentary Monday.

"In essence, candidate Lee Jae-myung and the Democratic Party are staging a 'special counsel inspection show' while trying to avoid the eyes of the people and evade suspicions of involvement in the Daejang-dong scandal."

The ruling Democratic Party of Korea a day earlier called on Yoon to respond to accusations about his "problematic" investigative decisions when he was a prosecutor. The party denounced Yoon for avoiding the questions by saying he couldn’t remember.

"The People Power Party and candidate Yoon Seok-youl have resorted to saying 'I can’t remember' whenever they fall in disadvantageous situations," the ruling party’s public relations team said in a statement Sunday.

"Until when are you going to show this cowardly attitude of hiding behind memories? This attitude only emphasizes how he, if he becomes the supreme leader, will hide corruption by his close aides. We will watch when that memory returns."

While Lee and Yoon both announced presidential promises and made efforts to publicize them in their campaign events, the election has been riddled with denunciations both ways.

The ruling party has also criticized Yoon and his party for failing to launch a fully prepared election campaign committee, while the People Power Party has denounced Lee for his past behaviors and moral standards while he worked as an attorney.

He faces growing criticism for arguably downplaying a case involving his nephew, who brutally killed two women in 2006. He provided the legal defense for his nephew and mentioned mental illness in his defense, which opponents also said was problematic.

Yoon has been criticized over suspicions surrounding his wife and her family. His wife, Kim Keon-hee, is alleged to have been involved in a Deutsch Motors stock manipulation case, and she is alleged to have committed academic plagiarism.

Kim's mother was jailed for establishing a medical foundation and a geriatric hospital in 2013 without the necessary medical qualifications. She was sentenced to three years in prison in July.

The so-called negative campaign battle comes as Yoon maintains a lead over Lee in a hypothetical multicandidate race as seen from poll results.

According to a survey of 3,023 adults by Realmeter released Monday, Yoon was ahead of Lee by 9.4 percentage points, with 46.3 percent support vs. 36.9 percent for Lee. The survey had a margin of error at plus or minus 1.8 percentage points with a 95 percent confidence level.