The main opposition Liberty Korea Party(LKP) has vowed to block the ruling and three opposition parties' agreement on Sunday to tie the 300-seat parliament to the percentage of voter support for each party.

At an emergency meeting of its lawmakers and members at the National Assembly Memorial Hall on Monday, LKP leader Hwang Kyo-ahn accused the Moon Jae-in administration of colluding with the minor parties to establish a leftist coalition through next year's general elections.

The LKP strongly objected to the four parties’ agreement to fast track the bill that would tie voter support to parliamentary seats without approval from a relevant committee.  

Hwang also criticized two other bills placed on the fast track. One of the bills would establish an independent body to probe high-ranking officials and the president’s family, while the other would adjust the investigative authority of the police and prosecution.

He said the administration was staging a "legislative coup" to extend the life of the "leftist dictatorship."

LKP floor leader Na Kyung-won said the country is at a crossroads between moving towards a dictatorship and maintaining a democracy.