Kim, a three-term lawmaker, had suffered from Parkinson's disease for years, apparently stemming from complications caused by tortures he underwent during past authoritarian regimes in the 1980s.

Kim entered politics in 1996 when he was elected as a lawmaker for Mokpo, a southwestern town known as a stronghold for the Millennium Democratic Party, the predecessor of the current ruling Democratic Party.

He lost his parliamentary seat, however, in 2006 after he was sentenced to a suspended jail term in connection with an influence peddling scandal. He was granted presidential amnesty a year later.

His relationship with his late father went beyond the usual father-son connection. Kim served as a key aide to his father during his turbulent years in the opposition, when he suffered oppression and close surveillance.

Kim Dae-jung served as president of South Korea from 1998-2003 and passed away in 2009. He was known for his lifelong commitment to fighting for democracy and improving inter-Korean peace.

He held the first-ever inter-Korean summit in 2000 with then-North Korean leader Kim Jong-il. He won the Nobel Peace Prize the same year for his role in bringing peace to the Korean Peninsula with the so-called Sunshine Policy of engaging with North Korea.

Political parties expressed condolences for Kim Hong-il's death.

"Kim had long devoted his life to our democracy and peace on the Korean Peninsula," Rep. Hong Ik-pyo, spokesman of the ruling Democratic Party, said.

The main opposition Liberty Korea Party also expressed condolences for his death.

"Many people who know his patriotism and work in parliament will be greatly saddened," Rep. Min Kyung-wook, LKP spokesman, said. "We pray that he will rest in peace."

He is survived by his wife and two daughters. (Yonhap)