South Korea's state-run pension fund chief was detained Wednesday in a widening probe to determine whether President Park Geun-Hye forced companies including Samsung to offer bribes, a spokesman said.

South Korea's ruling conservative party officially split Tuesday over the impeachment of scandal-hit President Park Geun-Hye, threatening to complicate presidential elections that could be held as soon as March.

A handful of South Korean lawmakers on Monday finally got to question the woman at the heart of the impeachment crisis surrounding President Park Geun-Hye, after she snubbed a televised hearing at her detention centre.

South Korea's scandal-hit president was asked to clarify the mystery surrounding her whereabouts at the time of a disastrous 2014 ferry sinking Thursday as the Constitutional Court opened her impeachment hearing.

Choi Soon-Sil, the woman at the centre of a corruption scandal that triggered the biggest political crisis for a generation in South Korea, denied all charges as her fraud trial opened on Monday.

A South Korean parliamentary probe into a corruption scandal engulfing President Park Geun-Hye sought Wednesday to compel the woman in the eye of the storm to answer questions after she rejected a summons.

South Korea lawmakers on Monday kicked off an unprecedented series of hearings that will grill the country's business elite over a corruption scandal engulfing impeachment-threatened President Park Geun-Hye.

A vote to impeach South Korea's scandal-hit president could take place as early as next week, lawmakers said Thursday.

South Korean prosecutors said Sunday that President Park Geun-Hye colluded with her close confidante in a corruption and influence-peddling scandal that has sparked massive nationwide protests and calls for her impeachment.

Tens of thousands of banner-waving protestors marched through the streets of Seoul on Saturday, demanding President Park Geun-Hye resign, a day after she apologised and accepted full blame for a crippling corruption scandal.