"If the ruling party really wants the agreement's ratification, it should first take several steps by taking into account opposition parties' opinions, rather than pushing ahead with the approval," Kim Kwan-young, the floor leader of the BP, said at a meeting with party members.

"We need the government to calculate the implementation cost in a frank manner. The government was not candid when it submitted an estimated cost only for next year," he said. "North Korea should also take corresponding procedures for the deal's approval in line with the South's move."

Whether rival parties will ratify the summit agreement is expected to be a hot-button issue at the ongoing parliamentary regular session.

The parties earlier agreed to handle the issue after President Moon Jae-in's trip to Pyongyang for his summit with North Korean leader Kim Jong-un from Sept. 18-20.

The ruling Democratic Party wants the April deal to be ratified at an early date to buttress Moon's peace initiative. But the conservative LKP and the BP remain lukewarm, citing a lack of practical progress in North Korea's denuclearization.

President Moon hopes inter-Korean summit agreements can survive government changes through parliamentary ratification. The summit agreements in 2000 and 2007 were not ratified, which led their implementation to fizzle out under succeeding conservative governments.

The ratification motion should be passed through the committee on foreign affairs and unification before being putting for a vote at a plenary session.

It is impossible for the DP to unilaterally handle the proposal, given that it controls 129 seats at the 299-member parliament. Its passage requires a vote attended by more than 50 percent of lawmakers.

In a positive sign, the BP on Wednesday proposed studying ways to comprehensively ratify the April summit deal and the latest summit declaration clinched in Pyongyang, as well as the military agreement.

"Only the LKP tries to hamper the Pyongyang summit deal, but we will seek cooperation with other parties that support denuclearization of the Korean Peninsula and a peace regime," Hong Young-pyo, the floor leader of the DP, said at a meeting with party officials. (Yonhap)