The main parties are expected to clash this week at parliament, as confirmation hearings for controversial Cabinet nominees and investigations into the April ferry accident resume on Monday.
Ruling Saenuri Party lawmakers are under political pressure to ensure nominees pass the hearings to complete President Park Geun-hye's Cabinet reshuffle, after two prime ministerial candidates dropped out amid spiraling allegations and criticism.
Opposition legislators, on the other hand, are looking to torpedo questionable Cabinet hopefuls, with National Intelligence Service director nominee Lee Byung-kee topping their blacklist.
The opposition for weeks has been emphasizing Lee's involvement in a 2002 political scandal.
Lee was fined for possessing illicit political funds while serving as an advisor to Lee Hoi-chang, a conservative candidate in the 2002 presidential elections.
Lee Byung-kee, according to court documents, handed 500 million won (S$617,000) to an aide of Rep. Rhee In-jae, a rival of Lee Hoi-chang at the time, in order to "convince" Rhee not to run.
Nominee Lee said he will explain himself at his confirmation hearing on Monday.
Kim Myung-soo, education minister-designate, and Chung Sung-keun, culture minister nominee, are expected to face a grilling by the opposition on Wednesday and Thursday, respectively.
Kim has been accused of plagiarizing a student's paper in 2002 as a professor at Korea National University of Education.
Chung has been under attack for drunk driving in 2005 and speculating in real estate in the early 2000s.
President Park's public approval ratings have dropped since Moon Chang-keuk in June and Ahn Dae-hee in May stepped down from their prime ministerial nominations.
Moon was accused of harbouring pro-Japanese leanings, Ahn of receiving special treatment in the legal industry after retiring as a justice of the Supreme Court in 2012.
This week's confirmation hearings could exacerbate Park's public ratings if candidates succumb to opposition pressure.
But the opposition could concentrate its political firepower at the government hearings on Thursday when Park's Chief of Staff Kim Ki-choon visits the National Assembly.
The government hearings are part of the ongoing parliamentary investigations into the Sewol accident on April 16 that left more than 300 dead or missing.
Since June 30, legislators have been inviting senior government officials to parliament to answer questions about the botched rescue operations for the sinking.
But because Kim is also head of Cabinet personnel management, opposition lawmakers are expected to blast him for nominating "unfit" candidates to minister-level positions.
Saenuri lawmakers, meanwhile, are threatening to boycott the panel hearings this week, in what critics say is a cheap political ploy to avoid the opposition's attacks.