This week the conservative Saenuri Party -- the New Frontier Party -- chose Park Geun-hye, daughter of a former dictator, as its presidential candidate for national elections in December.
Park's father was former junta general Park Chung-hee, who seized power in a military coup in 1961. He was elected president in 1963, a post he held until he was killed in October 1979.
Park, the first woman to lead a main South Korean political party into a presidential race, made the surprise graveside visit her first activity as the official presidential candidate of the Saenuri Party -- called the Grand National Party until February.
The visit to the grave of late liberal President Roh Moo-hyun was a symbolic gesture to win support from political opponents, Yonhap News Agency reported.
Park, 60, said she went to Roh's hometown of Bonghwa in North Gyeongsang Province to pay her respects to Roh, an icon of the liberal camp, out of her respect for his contribution to the country, Yonhap said.
"The pain I had was beyond description when I lost both of my parents all of a sudden," she said. "I fully understand how much it would have broken the heart of his wife, Kwon (Yang-sook)."
But main opposition Democratic United Party officials said Park's sudden visit to Roh's grave was a "political show" that lacked sincerity, a report by The Korea Times said.
The Saenuri Party heavily criticized Roh, a former human rights lawyer, for being incompetent when he was in power.
Representative Jung Sung-ho, spokesman for the DUP, said Park should have issued a formal apology for the misdeeds of her and her father before making such a controversial visit.
"President Roh passed away because of the Lee Myung-bak administration and political prosecutors," he said, arguing that Park appears to be only interested in securing more votes.
"Her visit is just a show that hurts the feeling of Roh's bereaved family members."
Roh committed suicide at the age of 62 in May 2009 by jumping off a cliff.
The front-runner in the DUP's presidential primary race, Moon Jae-in, was chief of staff to Roh while he was in office from 2003-08.
Roh, who was under investigation in a corruption scandal, didn't contest the December 2007 national election that was won by the conservative Grand National Party candidate Lee Myung-bak.
The South Korean electorate also was worried about worsening relations with the United States, rising housing prices and unemployment among the young, a report by The New York Times said just after Roh's death.
Park also visited the National Cemetery to pay respects to former President Syngman Rhee, her father and former President Kim Dae-jung.