Large crowds of South Koreans gathered on New Years for another rally demanding the removal of impeached President Park Geun-hye, who is determined to restore her powers through a court trial.

Carrying signs and candles and blowing horns, people packed a boulevard in front of an old palace gate that has been the centre of massive but peaceful protests in recent weeks.

Marches were planned near Seoul's presidential palace and the Constitutional Court.

Ms Park's supporters rallied in nearby streets, surrounded by thick lines of police.

The court has up to six months to decide whether Ms Park should permanently step down over a corruption scandal or be reinstated.

The judges said on Friday that Ms Park could not be forced to testify in the impeachment trial during the argument phase set to begin next week.

Protest organisers estimated that nearly 9 million people took part in anti-Park rallies nationwide in the previous nine Saturdays.

The biggest protest movement in the country's history pushed politicians to vote for Ms Park's impeachment on December 9.

State prosecutors have accused Ms Park of colluding with a longtime confidante to extort money and favours from the country's largest companies and allowing the friend to manipulate her administration.

Ms Park has apologised for putting faith in her jailed friend, Choi Soon-sil, but has denied any legal wrongdoing.

AP