Park Geun-hye, the daughter of South Korea's former military strongman Park Chung-hee, offered a public apology Monday to the victims of her father's 18-year rule as her approval ratings headed south ahead of the December presidential election.

Park, the presidential candidate of the conservative ruling Saenuri Party, had hitherto been reluctant to offer an outright apology and defended her father's 1961 military coup as an " inevitable" decision that helped modernize the country.

Her view on the late dictator's controversial legacy, which is still subject to fierce partisan debates here, was attributed to a sudden decline in her poll ratings just as her liberal rivals were gaining traction.

"I offer a sincere apology to those who suffered," the 60- year-old said in a press conference, apologizing for the coup, the 1972 constitutional amendment that strengthened Park Chung-hee's iron grip on power, and the "Inhyukdang" incident that led to the infamous execution of dissidents.

"(The incidents) violated the constitutional values and delayed political progress," said Park, who remains widely popular among conservatives and old-timers nostalgic for the country's rags-to-riches economic rise under the senior Park's rule.

She also acknowledged many suffered from dismal working conditions as they rebuilt the war-torn country and human rights were violated by the authorities in the name of deterring communism.

The first woman to clinch a presidential nomination from a major political party, the five-term lawmaker said she will establish a committee tasked with shedding light on historical issues for national unity.

"We now need to move from hatred to tolerance, from division to unity, and from the past to the future," she said.

Her belated mea culpa met with mixed reactions.

Family members of "Inhyukdang" victims, who were cleared of charges more than 30 years after they were sentenced to death for anti-government activities, said declining poll ratings must have forced Park to apologize.

Park's rivals, Moon Jae-in of the center-left Democratic People's Republic of Korea and popular entrepreneur-turned- professor Ahn Cheol-soo, cautiously welcomed the move.

Moon, who was jailed in the 1970's for protesting against Park Chung-hee's military rule, called for follow-up measures that would prove her sincerity.

The presidential election will be held on December 19. The incumbent President Lee Myung-bak, who defeated Park in the 2007 presidential race, is barred by constitution from re-election.