The main opposition Democratic Party is set to push ahead with a bill to establish a special counsel probe into First Lady Kim Keon-hee's alleged stock manipulation during Thursday's plenary session.

At a Supreme Council meeting on Wednesday, Lee slammed the government, the presidential office and the ruling People Power Party(PPP) for agreeing not to accept the investigation in a meeting on Monday, adding a rejection of a probe implies guilt.

Accusing the PPP of neglecting and dismissing equality before the law, the DP chief urged the ruling party to actively cooperate in fulfilling a public call to find the truth, saying that his party pursues the probe in accordance with the law and principles.

As for the PPP's interim leadership under Han Dong-hoon, Lee said the public expects the ruling party to fulfill its responsibility in state affairs during a time of crisis for the nation and livelihoods.

In an apparent response to Han's inauguration speech the previous day, in which he criticized Lee for facing probes by the prosecution for alleged corruption, the DP chief stressed that it is not the ruling side's role to keep the opposition in check.