The trial of ousted South Korean President Park Geun Hye began Tuesday at a Seoul court, with a lawyer for the former leader denying a string of allegations against her including bribery and abuse of power.

Park, 65, was indicted last month on 18 charges including demanding or taking 59 billion won (about $52 million) in bribes, abuse of power and leaking confidential information.

In the trial which began around 10 a.m. at Seoul Central District Court, Park's lawyer denied all charges, saying the indictment is "based on imagination."

Park became the country's first democratically elected leader to be dismissed from office when the Constitutional Court on March 10 upheld a parliamentary impeachment vote against her, effectively stripping her of immunity from criminal prosecution.

After prosecutors arrested Park on 13 criminal charges in late March, they increased the number of criminal charges against her to 18 following five rounds of questioning.

Park arrived at the court in handcuffs and dressed in a dark blue suit, with a badge showing her inmate number 503. It was her first public appearance since her arrest in late March, as she did not attend two preparatory court sessions where her attendance was not mandatory.

At the hearing, she said she was "unemployed," when asked about her job. Park has denied all allegations against her and is expected to do so during the trial.

The trial could take several months. If convicted of bribery, Park could be sentenced to life in prison.

Park is the daughter of assassinated military ruler Park Chung Hee, and the first South Korean leader put on criminal trial since the mid-1990s when two former military strongmen - Chun Doo Hwan and Roh Tae Woo - were convicted of and imprisoned for corruption and mutiny.

South Korea's first female president stands accused of letting a private citizen and confidante, Choi Soon Sil, meddle in state affairs and gain unauthorized access to classified documents.

Park is also suspected of colluding with Choi to extort massive donations from dozens of South Korean conglomerates, including the Samsung Group and the Lotte Group, for two nonprofit foundations under Choi's control.

On Tuesday, the 60-year-old Choi, who has also denied any wrongdoing, joined Park in court. The judge is expected to decide whether the two are to be tried together or separately.

At a preliminary hearing last week, the court said it would merge the two cases to avoid summoning the same witnesses twice, but Park's lawyers opposed the move, saying it could create bias.

It was the defendants' first face-to-face meeting since the scandal surfaced in autumn of last year.

Lotte Group Chairman Shin Dong Bin, who is accused of offering bribes to Park and Choi, also appeared at the trial.

The court plans to hold hearings two to three times a week and is expected to deliver the verdict by mid-October.

The corruption scandal that rocked South Korea in recent months also led to the arrests of dozens of people, including former Cabinet ministers, presidential secretaries and the heir-apparent of the Samsung Business Group, Lee Jae Yong.

Lee, the 48-year-old vice chairman of Samsung Electronics Co, is suspected of bribing Park and Choi in exchange for the state-run pension fund's backing of a merger of two Samsung affiliates in 2015, a move believed aimed at propelling him to the top of the Samsung Business Group.

Lee has effectively led the Samsung group since his father, Chairman Lee Kun Hee, suffered a heart attack in May 2014. The third generation business tycoon has denied any wrongdoing.