The main opposition Democratic Party demanded Friday that President Park Geun-hye reshuffle her Cabinet and presidential office over the acquittal of a key suspect in a high-profile election-meddling scandal.

The suspect, former Seoul police chief Kim Yong-pan, was acquitted Thursday of charges of scaling back and whitewashing the results of a police investigation into allegations of the state meddling in the 2012 presidential campaign.

In handing down the ruling, the Seoul Central District Court cited insufficient evidence.

"It is a difficult ruling for the public to accept," DP chief Kim Han-gil said at a Supreme Council meeting. "It showed how a court ruling can be influenced when the ruling forces go all-out to disrupt an investigation in an organized manner."

He expressed fury at the Park administration for what he said was "outright interference" in the prosecution's investigation into the election-meddling scandal and demanded a special independent probe.

DP floor leader Jun Byung-hun went further to demand a mass resignation of the Cabinet and a complete reshuffle of presidential secretaries.

He especially accused Justice Minister Hwang Kyo-ahn of playing a direct role in the prosecution's "shoddy investigation" and demanded Park fire him immediately.

"From Minister Hwang, who degraded the justice ministry into an organ of unlawfulness and injustice, to presidential chief of staff Kim Ki-choon, who is known for covering up the truth regarding the illegal presidential election, public confidence in the Park Geun-hye government's personnel has ended," Jun said at the meeting.

He added that Park's dismissal of Maritime Minister Yoon Jin-sook on Thursday isn't enough as other ministers, including Finance Minister Hyun Oh-seok and Education Minister Seo Nam-soo, have also lost public confidence.

Yoon was fired over her insincere attitude and numerous gaffes in handling a recent oil spill off the country's southern coast. (Yonhap News)