Official campaigning for local elections and parliamentary by-elections will kick off Thursday amid predictions that the liberal ruling party will comfortably win the June 13 polls, aided by high public support for President Moon Jae-in.

The 13-day campaign period will last until the eve of the elections, widely seen as a barometer for Moon's first year in office. Moon took office in May last year.

Up for grabs in the quadrennial local elections are 17 chiefs of provinces and metropolises, 226 heads of smaller administrative units, 824 seats in provincial and metropolitan assemblies, 2,927 lower-level local councilors and 17 superintendents of education.

Parliamentary by-elections will also be conducted in 12 districts nationwide. It marks the first time that the two elections will be held simultaneously.

The ruling Democratic Party stands at an advantage as it enjoys a high approval rate on the back of optimism about rapprochement on the Korean Peninsula following Moon's summit with the North's leader in late April.

The main opposition Liberty Korea Party is still reeling from public mistrust following the corruption scandal that led to the ouster of former President Park Geun-hye.

In the latest poll by Gallup Korea released on May 18, the DP's approval rating stood at 51 percent, far ahead of the LKP's 11 percent.

The biggest battleground of the local elections is the country's capital, where current Mayor Park Won-soon is seeking a third term, running against Kim Moon-soo of the main opposition Liberty Korea Party and Ahn Cheol-soo of the minor Bareunmirae Party.

Park is clearly ahead with 46.9 percent support, compared to Ahn's 20.6 percent and Kim's 12.9 percent, according to a survey commissioned by the Leader, an affiliate of online news outlet MoneyToday.

The Seoul mayorship carries extra weight as it is often deemed a steppingstone to the presidency.

Ahn, a former presidential candidate, was a front-runner ahead of the 2011 by-election for Seoul mayor but later dropped his bid and supported Park.

Kim, a former two-time governor of nearby Gyeonggi Province, is a well-known far-right politician. It was speculated that Ahn and Kim might merge their candidacies, but chances for that do not appear high.

As for Ahn's support in 2011, Park hinted that he has no burdens in mind on the grounds that he and Ahn belong to different parties and have walked on different political paths.

The ruling party is optimistic for strong performances in major constituencies, even in traditional turfs of the conservative LPK.

A potential setback for the ruling party may be an online opinion rigging scandal involving Kim Kyoung-soo, a former DP lawmaker who has close ties to Moon. Kim is running for the governor of South Gyeongsang Province in the June elections.

The scandal centers on allegations that Kim knew and communicated with a power blogger, known by his nickname Druking, who rigged online comments on news stories with his team in a bid to sway public opinions on hot-button political issues.

On May 21, the National Assembly passed a bill on the appointment of a special counsel to probe the scandal. The blogger claimed that Kim tacitly agreed to his campaign for the online comment rigging, an allegation flatly denied by the ex-lawmaker.

Pre-election opinion polls show that Kim does not appear to be affected by the scandal.

The approval rate for Kim came in at 50.6 percent, higher than 25.2 percent for Kim Tae-ho, a former two-term lawmaker of the LKP, according to a survey commissioned by the broadcaster KBS on 800 voters living in the province.

Meanwhile, the upcoming parliamentary by-elections will affect the formation of parliamentary standing committees for the second half of the 20th National Assembly's four-year term.

They will be the third-largest parliamentary by-elections ever, after the 2002 and 2014 votes, in which 13 and 15 seats were contested, respectively.

Parliamentary Speaker Chung Sye-kyun's two-year term ended Tuesday, but parties have yet to reach an agreement over a vote on Chung's successor and the composition of committees as the LKP insists that the work should be delayed until after the local elections.

In the 288-member parliament, the governing DP holds 118 seats, followed by the main opposition LKP with 113 seats. Three smaller opposition parties -- the Bareunmirae Party, the Party of Democracy and Peace and the Justice Party -- have 30, 14 and six seats, respectively.

Historically, local elections have not been affected by geopolitical developments. But the recent rapprochement between the two Koreas and the prospect of a historic summit between the United States and North Korea has sustained public support for Moon and the ruling party.

Moon and North Korea leader Kim Jong-un held the third-ever inter-Korean summit on April 27, reaching a landmark agreement to push for denuclearization, peace and inter-Korean cooperation. They held their second summit last Saturday to salvage the summit between Kim and US President Donald Trump after Trump withdrew from the meeting on Thursday, citing "tremendous anger and open hostility" from the North.

In the wake of North Korea's conciliatory message and Moon's surprise second meeting with Kim, Trump suggested that his meeting with Kim is likely to go forward as originally planned in Singapore on June 12, one day before the local elections.

The ruling DP welcomed the Moon-Kim summit, assessing it as an effort to rekindle the peace-building process on the peninsula. But the LPK lashed out at Moon's efforts, saying North Korea's denuclearization should be made in a "complete, verifiable and irreversible" manner. (Yonhap)