Gyeonggi Gov. Lee Jae-myung said Monday he feels "betrayed" by a former aide arrested over a massive development corruption scandal, once again disavowing any connection to the case threatening to mar his presidential campaign.

Lee made the remark ahead of the National Assembly's audit of his government, referring to Yoo Dong-gyu who served as acting president of Seongnam Development Corps. in charge of the development project in Seongnam, south of Seoul, when Lee was its mayor.

Yoo was arrested earlier this month on charges of breach of trust and bribe-taking.

"I still can't believe it myself, but if the court arrested him ... there must be something wrong," Lee told reporters before attending the audit at the Gyeonggi provincial government office in Suwon, just south of Seoul. "It's truly regrettable and from a personal standpoint, I feel betrayed," he said.

The audit by the National Assembly's Public Administration and Security Committee opened at the Gyeonggi provincial government office amid intense media coverage of the scandal and its potential impact on Lee, the presidential nominee of the ruling Democratic Party.

Lawmakers of the main opposition People Power Party have vowed to use the audit to prove their suspicions that Lee, as mayor of Seongnam at the time, masterminded a corrupt scheme to award a little known asset management firm 1,000 times the amount it invested in a project that developed the Daejang-dong district in Seongnam into residential complexes.

Lee, who has denied any connection to the scandal, is expected to use the audit to try to clear his name and remove a major obstacle in his campaign for the nation's top elected office, with less than five months to go until the presidential election on March 9.

Another key question is the identity of an unnamed person cited in a phone conversation between two other suspects in the case. In the audio recording, Kim Man-bae, the owner of the asset management firm, Hwacheon Daeyu, is heard denying that he is the owner of one of Hwacheon Daeyu's seven affiliates and claiming that half of it belongs to the unnamed person.

The opposition party has claimed the person is Lee.

Suspicions also abound as to whether Hwacheon Daeyu, a fledgling company, was given special favors in its selection as a partner in the development project.

Lee sought to assure his supporters that he will emerge unscathed.

"There are people who are worried that I will be humiliated by opposition lawmakers. But you do not have to worry too much," he wrote on Facebook on Sunday. "Through the audit, I will show humility and confidence as the person in charge of the Gyeonggi provincial administration. Even if there are political attacks, I will not be swayed and will respond in a dignified manner."

The questioning is set to continue Wednesday during another audit of the Gyeonggi government by the National Assembly's Land, Infrastructure and Transport Committee. (Yonhap)