The protesters also marched within 200 meters of the presidential office holding banners with messages such as "Arrest President Park."
At 8:00 p.m., participants are set to hold a blackout by putting out their candles, with ordinary citizens turning off their lights as a symbol of protest.
Police said they will deploy some 25,000 officers, despite previous protests ending peacefully.
This is the fifth rally since the outbreak of the scandal. Approximately 600,000 participants were present at the protest last week.
On October 24, media reported that Choi Soon-sil, a friend and "shadow adviser" of the president, allegedly received drafts of speeches and presidential documents, though she had never held a public post.
On November 20, the Seoul Central District Prosecutor's Office filed formal charges against Choi and two of Park's former aides and stated that Park was suspected of being an accomplice in the conspiracy. South Korea's main opposition Democratic Party (The Minjoo) has announced plans to seek vote on Park's impeachment in December. On Friday, Park's approval rating fell to a record-low of 4 percent.
