SEOUL (AFP) - The secret confidante of former South Korean president Park Geun-hye who played a central role in the corruption scandal that toppled the disgraced ex-leader had her prison sentence cut by two years on Friday (Feb 14) in a retrial.

Choi Soon-sil - who became close to Park through her father, a shadowy religious figure - initially received a 20-year prison term in 2018 for using her presidential connections to force companies to donate to foundations she controlled, among other charges.

The scandal exposed shady links between big businesses and politics in South Korea, with Lee Jae-yong, the vice-chairman of tech giant Samsung Electronics convicted of bribery, embezzlement and other offences.

Park was brought down in 2017 after huge street protests triggered by allegations that she and Choi took bribes in return for government favours.

But South Korea's Supreme Court last year sent Choi's case back to a lower court for a retrial - along with those of Park and Samsung's Lee - saying she should not be found guilty on some of the coercion charges.

Choi's crimes had caused "significant disruption in state affairs", the Seoul High Court said in its verdict on Friday, according to South Korea's Yonhap news agency.

"Social discord from Park's impeachment... still continues to this day," it added.

"Taking this into consideration, it is inevitable to hold Choi accountable," it said, fining her 20 billion won (S$23.5 million) and ordering her to forfeit 6.3 billion won.

Park's own retrial is continuing. She is currently serving a combined sentence of 32 years for bribery, abuse of power and election law violations.