Cooperation with opposition parties is critical to buttress the government-sponsored bills on reforms and people's livelihood as Moon has entered his second year in office.

But the main opposition Liberty Korea Party and the minor opposition Bareunmirae Party raised doubts about the sincerity of Moon's plan.

"This is not the stage (for Cheong Wa Dae to consider a bipartisan Cabinet)," Kim Sung-tae, the floor leader of the LKP, told a radio program on Tuesday.

He claimed that the Moon government is staging what he called political revenge in the name of "removing accumulated evils," referring to unraveling misconduct by former President Park Geun-hye and officials under her government.

Kim Kwan-young, the floor leader of the BP, called on the presidential office to take actions to show its willingness for cooperative politics.

"Cheong Wa Dae should first show its sincerity with concrete actions, not with words," Kim said at a meeting with party officials. "The presidential office should take a proactive approach, as to issues like its economic policy, constitutional revision and electoral reforms."

But the minor opposition Party for Democracy and Peace said that if Cheong Wa Dae makes an official offer, it could consider whether to accept it.

"The ruling party seems to have come to the sense that it cannot approve reform bills (without cooperation with opposition parties)," Cho Bae-sook, the chief of the liberal party, said. "If (Cheong Wa Dae) makes an official proposal, we will study it." (Yonhap)