South Koreans have gathered in large numbers at a New Year's Eve protest against their impeached leader, demanding her removal from power.
Large crowds formed near the presidential palace and constitutional court in the capital Seoul on Saturday.
Park Geun-hye was impeached this month by parliament, but the move requires approval from the constitutional court.
The head of the country's national pension fund was arrested on Saturday as the corruption investigation widens.
According to the special prosecutor, Moon Hyung-Pyo has admitted to putting pressure on the fund to approve an $8bn (£6.5bn; €7.6bn) merger of two Samsung group units when he served as health minister between 2013-15.
Saturday's demonstration was the latest in a series of protests against the president, which organisers say nearly nine million people have attended in total.
"I hope in 2017 we will see our democracy repaired," Lee Hae-jin, who has attended each of the last 10 protests, told the Associated Press news agency.
Some of President park's supporters also took to the streets, surrounded by thick lines of police.
Mr Moon's arrest followed a raid on the Samsung and the national pension fund offices amid an investigation into whether President Park had pressured the fund to support the merger. In return, Samsung was alleged to have given financial favours to the president's close confidante, Choi Soon-sil.
Ms Choi is currently in custody, facing charges of coercion and abuse of power.
Parliament in early December voted to impeach the president but the case rests with the constitutional court - which has up to six months to make a ruling.
Ms Park is suspended from her duties until the court makes a decision.
If it confirms her impeachment, she will be permanently removed from office, and elections will be held within 60 days.