Friday's overwhelming parliamentary vote to remove Park from office puts her fate in the hands of a nine-judge Constitutional Court, which has 180 days to decide whether to uphold the motion.

Park's powers have been suspended and assumed by Prime Minister Hwang Kyo-ahn, who has ordered a high state of military alert for any attempt by rival North Korea to take advantage of the political turmoil.

South Korea's finance minister warned on Sunday that the impeachment could weigh on the economy if sentiment was undermined.

Park, whose father ruled the country for 18 years after seizing power in a military coup, has been accused of colluding with a friend and a former aide, both of whom prosecutors indicted earlier, to pressure big businesses to donate to foundations set up to back her policy initiatives.

Park, who is serving a single five-year term ending in February 2018, has denied wrongdoing but apologised for carelessness in her ties with her friend, Choi Soon-sil.

Prosecutors on Sunday again characterised Park as a co-conspirator, media reported, although she has immunity from prosecution as long as she remains in office.

They made a similar assertion on November 20.

If the Constitutional Court affirms the parliamentary vote, Park would become the first democratically elected leader of Asia's fourth-biggest economy to be forced from office.

"Amid so much global uncertainty, this political situation is further weighing on the economy and a downturn in sentiment could be another problem," Finance Minister Yoo Il-ho told a news conference.

Protests

The two former officials whose charges were reported by media on Sunday included a former senior economic aide, Cho Won-dong, accused of colluding with the president in trying to pressure a South Korean conglomerate, CJ Group, to dismiss a group vice chairman, the Yonhap News Agency reported.

Cho told a parliamentary hearing on Wednesday he had found the arm-twisting wrong but he had to deliver the president's message to the conglomerate.

The chairman of food-to-entertainment conglomerate CJ Group, Sohn Kyung-shik, told a separate hearing that Cho had met him and asked the group to remove the vice chairman from her position.

The second newly charged person was a former vice culture minister, Kim Chong, indicted for suspected abuse of power and coercion for exerting influence over a state-run firm to make a contract with a sports management company controlled by the president's friend, Yonhap and other outlets reported.

Prosecutors were not immediately available for comment.

A spokesman in the presidential Blue House declined to comment.

The scandal blew up in October and has drawn large, festive street protests in Seoul for the past seven Saturdays, with the crowds calling for Park to step down immediately.

A candle-lit rally on Saturday drew a smaller crowd of about 120,000 at its peak, police said, although organisers put the total number of participants at 800,000.

North Korean state media has been scathing in its coverage of the scandal.

On Sunday, it said North Korean leader Kim Jong Un guided a special operations drill targeting the South. Pictures in the North's Rodong Sinmun newspaper showed what appeared to be a mockup of South Korea's presidential Blue House as a target.

The United States, which has about 28,500 troops stationed in South Korea, was in close contact with South Korea and remained a strong ally, the White House said late on Friday.