Gyeonggi Province Gov. Lee Jae-myung on Sunday extended his lead in the Democratic Party’s primaries, coming in top in the North Jeolla primary.

With Sunday’s victory -- with 54.5 percent of the votes -- Lee Jae-myung solidified his lead over former Prime Minister Lee Nak-yon, who had broken the Gyeonggi governor’s winning streak on Saturday.

The former prime minister, who had won the South Jeolla primaries by 122 votes on Saturday, came in second with 38.4 percent of the votes.

Lee Nak-yon had been appealing to party members saying that he is a candidate with “no moral flaws,” pointing out that he is running up against a governor who is embroiled in a controversy over a development project in Daejang-dong while he was a mayor of Seongnam, Gyeonggi Province.

“Many people are angry over the development corruption in Daejang-dong, Seongnam. I will thoroughly dig into the corruption and punish anyone involved according to the law,” the former Prime Minister said.

The project in Daejang-dong is a housing site development project worth 1.15 trillion won ($976 million) promoted by Lee when he was reelected as Seongnam Mayor in 2014. The controversy centers on the involvement of Seongnam Park Co., which was selected as the preferred consortium for the project, and Hwacheon Daeyu, a dubious company that participated with a 1 percent stake, a capital of 50 million won. A former reporter, who interviewed Lee before the project started, founded Hwacheon Daeyu, a week before a private-sector tender for the participation in the project began.

Hwacheon Daeyu was able to earn enormous dividends and real estate profits through the project. Although nothing else was revealed about the relationship between Hwacheon Daeyu and Lee, questions are being raised on whether Lee, who had authority to permit and approve construction works related to the project, may have given certain favors to help the company reap profits.

Despite the recent loss and the lingering speculation, Gov. Lee is still a solid candidate to win the party primary. He won five regional primaries and the first “super week,” with a cumulative 53 percent of the votes. Lee Nak-yon had a cumulative 34 percent of the votes. Choo Mi-ae came in third with 10 percent. The party will determine the final presidential candidate on Oct. 10.

In the main opposition People Power Party, former Prosecutor General Yoon Seok-youl was the undisputed front-runner until last month. While Yoon is embroiled in several political allegations, Rep. Hong Joon-pyo, a strong contender in the opposition bloc, has been gaining support.

According to a poll released on Sunday, both Yoon and Hong would beat Gov. Lee in a two-way race.

The polling firm Realmeter showed that Yoon had 43.1 percent support in a race against Lee, winning by 6.1 percentage points. Hong also came ahead of Lee by 2.6 percentage points, with 38.2 percent support.

Yoon beat Gov. Lee in all regions except Gwangju, South Jeolla Province and North Jeolla Province, and all age groups except those in their 40s. Hong received more support from Seoul, men, people in their 20s and 30s, the self-employed, and independents.

The opposition party will finalize its candidate on Nov. 5.