Chung Mong-koo, the imprisoned chairman of the Hyundai Group, has been allowed to oversee group management from behind bars, according to his prosecutors, Asia Pulse reported.

Chae Dong-wook, a senior prosecutor, said Chung has been allowed to have extended, though not long, meetings with group executives for discussions on key management affairs.

Chung is being held on charges of embezzling 120bn won ($US127m) to create secret funds, which were then used to bribe politicians in return for business favours and to facilitate the transfer of wealth and corporate control from Chung Mong-koo to his son Chung Eui-sun, chairman of Kia Motor.

Prosecutors have estimated that damages to Hyundai Motor and its affiliates are in the region of 390bn won.

The arrest has raised fears that the automaker's overseas expansion plans could be halted.

The 68-year-old chairman has been questioned about the bribery and embezzlement charges every day since Monday.

Prosecutor-general Choung Sang-myoung has reportedly asked senior prosecutors to help minimise economic fallout from the tycoon's arrest.

"He's doing well and admitted to parts of the charges," Chae said, confirming that he will be indicted around the middle of this month.