Supporters and opponents of ousted President Park Geun-hye staged rival mass rallies in central Seoul on Saturday as prosecutors mull over whether to seek to arrest the country's former leader on multiple corruption allegations.

Anti-Park protesters have taken to the streets each Saturday since late last year until the Constitutional Court upheld the parliament's decision to remove Park from office earlier this month. 

They held another candlelight vigil in Gwanghwamun Square in central Seoul from 6 p.m. to demand the detention of the scandal-hit former president and her former aide Woo Byung-woo.

Prosecutors are mulling over whether to seek an arrest warrant after they carried out a marathon interrogation of Park from Tuesday to Wednesday. She is known to have denied all allegations raised against her.

Woo, a former senior secretary for civil affairs, is suspected of aiding and abetting Choi Soon-sil, Park's friend of 40 years, in meddling in state affairs and disrupting a special presidential inspector's investigation into the influence-peddling scandal. He is one of the last figures embroiled in the massive scandal to avoid arrest so far.

Prosecutors on Thursday visited the presidential office Cheong Wa Dae for a search and seizure of his office, but were denied entry due to security reasons.

The protesters also called for a thorough reinvestigation into the 2014 sinking of the ferry Sewol, which killed 295 people and left nine still missing. Nearly three years after the country's worst maritime accident, the hull of the ship was raised from the water this week to search for the missing people.

The protesters marched toward the office of Acting President and Prime Minister Hwang Kyo-ahn from 7:30 p.m.

Park's supporters, meanwhile, held their rally just meters away near the city hall from 2 p.m., demanding the disbandment of the Constitutional Court and the National Assembly.

Some lawmakers including Rep. Kim Jin-tae, a presidential hopeful of the former ruling Liberty Korea Party, participated in the protest.

Police said they mobilized some 12,300 officials near the two demonstrations in case of contingencies.

The rallies held by pro-Park protesters have been turning violent recently, with some protesters attacking police officers and reporters on duty. (Yonhap)