Ousted South Korean President Park Geun-hye left prosecutors' offices early on Wednesday after being questioned in an investigation into a corruption scandal that ended her presidency this month.

Park did not respond to reporters' questions as she emerged from the building after nearly 22 hours and entered a waiting car to be driven to her private home.

Prosecutors questioned Park as a criminal suspect for the first time since the Constitutional Court on March 10 upheld her December impeachment by parliament.

Park is accused of colluding with a friend, Choi Soon-sil, to pressure big businesses to donate to two foundations set up to back the president’s policy initiatives.

She and Choi have denied wrongdoing.

Prosecutors declined to comment on Tuesday whether Park would be called back for more questioning or whether they will seek an arrest warrant from the court to detain her.

They did not discuss the details of the questions but said Park was responding well to the investigation.

Park, 65, became South Korea's first democratically elected president to be removed from office when the Constitutional Court on March 10 upheld her impeachment.

She issued a brief statement upon arriving at the prosecutors' office on Tuesday, her first public remark since being removed from office.

"I am sorry to the people. I will faithfully cooperate with questioning," Park said in front of media at the steps of the prosecutors' office building.

The questioning lasted 14 hours until just before midnight, one of her lawyers, Sohn Bum-gyu, told reporters.

She and her lawyers reviewed her statements made to the investigators, before leaving at 6:55 a.m. (2155 GMT Tuesday).

Park has not been charged but could face more than 10 years in jail if convicted of receiving bribes from bosses of big conglomerates, including Samsung Group [SAGR.UL] chief Jay Y. Lee, in return for favours.

Park's fate and the widening corruption investigation have gripped the country at a time of rising tension with North Korea and China.

Park smiled and briefly spoke to some of her supporters gathered outside her home before entering the gate without making public comments.