The main opposition Democratic Party (DP) said Monday it will boycott all parliamentary standing committees over the next three days in protest of the prosecution's disciplinary action against a whistleblower.

The boycott comes amid an ongoing political dispute between the ruling and opposition parties over a string of controversies, including state agencies' alleged meddling in last year's presidential election.

On Friday, the Supreme Prosecutors' Office (SPO) reportedly decided to recommend a three-month suspension for Yoon Seok-youl, a senior prosecutor who led an investigation into allegations that the state spy agency conducted an online smear campaign against then opposition presidential candidate Moon Jae-in ahead of last December's election.

Yoon has accused his superiors of trying to influence the investigation, while the SPO has accused him of violating due procedures.

"The prosecution's biased investigation, biased (internal) inspection and biased disciplinary action are effectively part of the government's scheme to end a fair investigation into the National Intelligence Service's interference in the presidential election as well as the related trials under way," Rep. Jun Byung-hun, the DP floor leader, said at a Supreme Council meeting.

"In order to stir up the public opinion against this, we have decided to temporarily suspend all parliamentary proceedings excluding the confirmation hearings."

Under the plan, DP lawmakers will still attend a set of parliamentary confirmation hearings for the nominees for chief of the Board of Audit and Inspection, health and welfare minister, and prosecutor general, which are scheduled for Monday through Wednesday.

Last Friday, the DP boycotted all parliamentary proceedings in protest of what it claimed was a politically driven prosecution investigation into a missing transcript of the 2007 inter-Korean summit.

On the same day, DP leader Kim Han-gil demanded a special investigation into all alleged irregularities surrounding last year's presidential race, saying the prosecution cannot be trusted to conduct a fair probe.

On Monday, he demanded President Park Geun-hye state her position on the proposal. Park returned from an eight-day trip to Europe on Saturday.

"Punishing Prosecutor Yoon, who led efforts to expose the truth behind the illegal intervention in the presidential election, is the same as punishing justice and (implies that they) will punish the public who demand the truth," Kim said at the Supreme Council meeting.

"The Democratic Party will never allow democracy to be trampled upon this land in any event."

Ruling Saenuri Party leader Hwang Woo-yea criticized the opposition party's moves as a plan to drive the National Assembly to "brain death."

"The opposition party has tied all bills and (next year's) budget to a special investigation into all crimes related to the presidential election," he said at his party's Supreme Council meeting. "(This) is anti-democratic and a model of old politics ...

We hope the DP will reconsider its demands for a special investigation and its suspension of parliamentary activities and return to the path to the National Assembly's normalization." (Yonhap News)