Park's daughter Park Geun-Hye is running in the December 19 election and last month apologised for the abuses which occurred under her father's leadership.
"The character and the personality of the film made it appropriate that it was released before the December elections," said Chung, speaking before the premiere at Asia's biggest film festival.
"I don't know how it will influence the presidential elections but I do hope it does influence the way people vote.
"As a filmmaker, if my work has social influence and if people are influenced by my message in the film, that is the most rewarding moment a filmmaker can have."
The film tells the story of democracy activist Kim Geun-tae, imprisoned and tortured by South Korea's notorious Korean Central Intelligence Agency (KCIA) in 1985 over alleged ties to the North and a plot to overthrow the government.
Starring Park Won-sang in the central role, it offers an unflinching look at the various torture methods used by the KCIA and has been greeted with a huge amount of interest -- and critical acclaim -- here at the festival.
Director Chung made no apologies for the often graphic nature of the production.
"I have been a filmmaker for 30 years and this film gave me the most difficult time of my career," he said. "If the audience has as difficult a time as I did, then I have achieved my goal."
"National Security" is based on Kim's autobiography and Chung said he had invited Park to the premiere.
Although the presidential hopeful was in the audience at the opening of the festival on Thursday night, it could not be confirmed whether or not she had accepted the invitation.
Chung had said before the festival that he "really wanted" Park to see the film and was unconcerned by the possibility it could be claimed the film revealed his own political leanings.
"I don't care how people look at it or label it," he said.
"Those who disagree with what I think, will look at it in a negative way for sure. But I don't care. Artists should unveil the irony of the society we live in. It is our duty."
Park's attempt to become South Korea's first woman president had been hampered by demands that she go public with her opinion about her father's 18-year rule, a time which still evokes strong and divided emotions across the country.
Some credit Park Chung-Hee with ensuring South Korea's economic rise following the 1950-53 Korean War and say his autocratic methods were needed during tumultuous times.
But others see him as a brutal dictator under whose rule any opposition was suppressed using false imprisonment, torture, and extra judicial execution.
Until last month's statement - broadcast live from her New Frontier Party headquarters - Park's ambiguous responses to such questions had helped allow her two rivals in the presidential race - the left-leaning Jae-In and Ahn Cheol-Soo - to close the gap on her lead in the country's leading opinion polls.
Director Chung is no stranger to controversy, with his previous production, last year's box office hit Unbowed, revisiting the case of a Korean math professor who fired a crossbow at a judge.
The Busan festival continues until October 13.
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