A poll showed that in the Seoul mayoral and Daegu mayoral races, the biggest battlegrounds of the June 3 local elections, candidates from the Democratic Party of Korea and the People Power Party are locked in neck-and-neck contests. In Busan mayor and South Gyeongsang governor races, both seen as key battlegrounds, and in Busan Buk-gap, where a National Assembly by-election is being held, the Democratic Party of Korea candidates are leading outside the margin of error. By contrast, in Pyeongtaek-eul, Gyeonggi, candidates from the Rebuilding Korea Party and the Democratic Party of Korea are in a dead heat.
In a survey commissioned by The Chosun Ilbo and conducted by polling firm Matrix on the 16th–17th, targeting a total of 3,200 voters (800 in each region) in Seoul, Daegu, Busan, and South Gyeongsang via 100% wireless telephone interviews, Chong Won-o of the Democratic Party of Korea recorded 40% support in the Seoul mayoral race, while Oh Se-hoon of the People Power Party had 37%. In the Daegu mayoral race, Kim Boo-kyum of the Democratic Party of Korea had 40% and Choo Kyung-ho of the People Power Party had 38%. All are within the margin of error (±3.5 percentage points), indicating close contests.
In the Busan mayoral race, Chun Jae-soo of the Democratic Party of Korea had 44% and Park Heong-joon of the People Power Party had 35%, while in the South Gyeongsang gubernatorial race, Kim Kyeong-soo of the Democratic Party of Korea had 44% and Park Wan-su of the People Power Party had 34%.
In Busan Buk-gap, where a National Assembly by-election is being held, Ha Jung-woo of the Democratic Party of Korea had 39%, Park Min-shik of the People Power Party had 20%, and independent Han Dong-hoon had 33% support. In the three-way race, Ha is leading outside the margin of error, but in head-to-head matchups it was "Ha 44%, Park 30%" and "Ha 41%, Han 39%."
In Pyeongtaek-eul, Gyeonggi, Kim Yong-nam of the Democratic Party of Korea had 25%, Yoo Ui-dong of the People Power Party had 20%, Cho Kuk of the Rebuilding Korea Party had 26%, Kim Jae-yeon of The Progressive Party had 6%, and Hwang Kyo-ahn of Freedom and Innovation had 11%. With Kim Yong-nam and Cho Kuk in a tight race within the margin of error (±4.4 percentage points), head-to-head matchups also showed Kim Yong-nam and Cho Kuk each leading Yoo Ui-dong by 18 percentage points and 11 percentage points, respectively.
This poll, commissioned by The Chosun Ilbo and conducted by polling firm Matrix on the 16th–17th, surveyed a total of 4,201 eligible voters residing in Seoul (800), Busan (800), Daegu (800), South Gyeongsang (800), and in Busan Buk-gap (501) and Pyeongtaek-eul, Gyeonggi (500), where National Assembly by-elections are being held. It was carried out via telephone interviews using virtual mobile numbers provided by the three telecom companies. The margin of sampling error for each region is ±3.5 percentage points at a 95% confidence level for Seoul, Busan, Daegu, and South Gyeongsang, and ±4.4 percentage points at a 95% confidence level for Busan Buk-gap and Pyeongtaek-eul, Gyeonggi. For details, see the National Election Survey Deliberation Commission website.