Former South Korean President Park Geun-hye left hospital on Thursday three months after she was released from prison where she spent nearly five years following a conviction on corruption charges.

Park, 70, became the country's first democratically elected leader to be forced from office when the Constitutional Court upheld a parliament vote in 2017 to impeach her over a scandal that also landed the chiefs of two conglomerates, Samsung and Lotte, in jail.

"As president, I tried to work hard for the country and the people but there are many dreams that were not achieved," Park, dressed in a dark navy coat and holding a purse, told hundreds of cheering supporters after arriving at her home in the southeastern city of Daegu.

"But those dreams are tasks for others," Park said, signalling no intention of returning to the political fray. "I will provide support so that talented people can contribute to the development of my hometown of Daegu and the country."

Park is the daughter of former dictator Park Chung-hee and her imprisonment divided a country in which old Cold War rivalry between right and left still shapes politics.

An unidentified object was thrown at Park shortly after she began delivering her televised remarks from a podium but she smiled and thanked the crowd.

"I am extremely grateful that so many people came to warmly greet me even though I had numerous shortcomings and disappointed you," she said.

The Supreme Court last year upheld Park's sentence of 20 years in prison for colluding with a friend, who was also jailed, to receive millions of dollars from the companies, mostly to fund her friend's family and non-profit groups.

Outgoing President Moon Jae-in, who heads a liberal administration, granted Park a special pardon in December, citing her deteriorating health and his hopes to move past the "unfortunate history" and promote national unity.

Earlier, as Park left the Samsung Medical Centre in Seoul, she told some 40 supporters that her health had improved. Dozens of officials who served in her administration and her conservative political party also gathered to offer their best wishes.

Park then visited her father's grave before heading home.

Park's release comes days after a presidential election won by conservative candidate Yoon Suk-yeol.

President-elect Yoon, who was in involved in the investigation of the corruption charges against Park when he served as prosecutor-general, said during the election campaign that he was sorry about what happened to her.

On Thursday, he said he hoped to meet her and would invite her to his inauguration in May.

Moon's office said he had sent Park an orchid and wished her well.