Chung arrived for questioning, and his son may follow

As he arrived at the prosecutors' office in Seoul, Mr Chung again offered an apology to the South Korean people.

The car giant is suspected of creating a slush fund to pay politicians and officials for business favours.

Mr Chung's son, Chung Eui-Sun, president of Hyundai subsidiary Kia Motors, faced questions last week.

Two lobbyists have been arrested on suspicion of receiving money from the car company, although it is unclear whether they actually sought to pay government officials.

In an act of public penance and to restore confidence in the firm's activities, Hyundai said Mr Chung and his son would donate their 60% stake in Glovis, another subsidiary, to charity.

Glovis, a logistics unit, has been at the centre of the investigation.