The main opposition People Power Party(PPP) won a sweeping victory in parliamentary by-elections, along with the win in the tight presidential race.

According to the National Election Commission on Thursday, the PPP claimed four out of five parliamentary seats up for grabs in the by-elections, which were held on the same day of the presidential election on Wednesday.

In Seoul, PPP candidate Choe Jae-hyeong won in the Jongno district with 52-point-09 percent of the vote, while Cho Eun-hee won in the Seocho-A district.

Outside of the capital, PPP candidate Chung Woo-taik won in Sangdang district in the central city of Cheongju and Kim Hack-yong clinched a victory in Anseong, Gyeonggi Province.

With the by-election results, the number of the PPP's seats will increase to 110 in the 300-member National Assembly.

Independent Lim Byung-heon won a seat in the southeastern city of Daegu.