State prosecutors have applied an exit ban on Cho's relatives and persons implicated in corruption scandals linked to his family's dubious investment in a private equity fund (PEF) and the operation of a private school foundation that his mother runs.

But Cho's wife and his mother were not subject to the travel ban.

Cho faces a series of corruption allegations that range from suspected undue college admission involving his daughter to his family's hefty investment in the PEF.

The prosecution carried out simultaneous raids on 20 institutions, including five universities and the office of the PEF operator, on Tuesday as part of its probe into Cho.

His wife, surnamed Jung, faces allegations that she sought to evade the gift tax after she invested over 1 billion won ($865,765) in the PEF with her two children.

Cho's brother-in-law also invested around 350 million won in the fund with his two sons, effectively making Cho's family and relatives all of the investors in the PEF.

Cho's family promised to invest 7.4 billion won in the fund, an amount that is far larger than its total wealth, two months after Cho was named as senior presidential secretary for civil affairs in May 2017.

The fund bought a firm that produces automatic switches for streetlamps, which later secured hundreds of orders issued by the government and saw an increase in sales.

The prosecution is also seeking to secure the whereabouts of three people involved in the fund's operation, including Cho's relative, as they left the country ahead of the prosecution's probe. It is persuading them to return home with help of their acquaintance.

"I am embarrassed as the prosecution has kicked off a probe ahead of a confirmation hearing," Cho told reporters. "But my family will faithfully undergo the investigations."

Political parties have agreed to hold a confirmation hearing for Cho next Monday and Tuesday, but they are still bickering over his scandals.

The ruling Democratic Party (DP) slammed the prosecution's Tuesday raids, raising doubts that the move may be intended to hamper President Moon Jae-in's drive for prosecution reform.

The president named Cho as new justice minister who will command the prosecution, apparently given his role in fleshing out Moon's vision to overhaul the elite investigative agency.

"The (prosecution's) move is an unprecedented act. It is an act that disturbs the country," DP chairman Lee Hae-chan told a meeting with members of the leadership's council.

The main opposition Liberty Korea Party (LKP) even considered the option of boycotting the confirmation hearing after floor leader Na Kyung-won said that it seems inappropriate to hold a hearing for a person who is subject to a prosecution probe.

But the party decided to go ahead with the session as scheduled during a lawmakers' meeting later in the day, at which many raised objections to the move on the grounds that it could cause a public backlash.

Later in the day, about 100 students and graduates of Pusan National University in the southern port city of Busan held a rally on their campus demanding that the school investigate allegations surrounding Cho's daughter, who attends its medical school.

"The school should form a fact-finding committee and look into possible illegality and unfairness regarding her admission, administrative affairs and scholarship," said Lee Jae-young, who led the candlelight vigil.

The nominee's daughter received a personal scholarship from a professor of the school despite her failing grades. Critics also alleged she received preferential treatment when she was listed as the first writer of an academic paper while attending high school.

Hundreds of students and graduates of Seoul National University also staged their second candlelight rally, demanding Professor Cho withdraw from the nomination. (Yonhap)