SEOUL (BLOOMBERG) - South Korean prosecutors raided the home of Justice Minister Cho Kuk, the Yonhap News Agency reported, as part of a widening corruption investigation that has already dented support for President Moon Jae-in.

Investigators entered Mr Cho's house shortly after 9am Monday (Sept 23), Yonhap said, citing the Seoul Central District Prosecutors' Office.

The move comes amid a range of inquiries into issues involving Mr Cho and his wife including their children's university applications and an investment in a private equity fund.

Mr Cho has denied wrongdoing.

The Seoul Central Prosecutors Office, the Justice Ministry and the presidential office declined to comment when reached by phone Monday.

The raid comes two weeks after Mr Moon appointed Mr Cho - a political ally and close confidant - despite parliamentary resistance to his nomination.

The president's approval rating slipped to a record low of 40 per cent last week, a regular Gallup Korea survey showed, as the appointment controversy, a slowing economy and setbacks in US-North Korea talks all weighed on his support.

Prosecutors are investigating how Mr Cho's daughter won admission to a prestigious university after she was credited as a main author of a published scientific paper while a high school student on a brief internship.

They're also looking into how his family made a hefty profit from a questionable investment in the private equity fund.

Mr Cho's university professor wife Chung Kyung-shim was indicted earlier this month on allegations that she interfered with the probe by forging documents, YTN reported. Ms Chung has denied the allegations in a Facebook post.

On Monday, prosecutors visited Mr Cho's home in southern Seoul to collect computer hard drives and numerous work-related documents, Yonhap said.

Investigators have visited numerous locations related to the probes, including the private equity fund's office and university campuses.