The LKP is targeting key fast-track bills on electoral reform and a corruption probe unit as the legislation is likely to be put to a full vote after Tuesday.

"A 'fast-track' train that got off to an illegal start is driving South Korea off a cliff of despair and downfall," LKP floor leader Na Kyung-won told reporters.

"The LKP will start a peaceful and legitimate journey of protests. In that sense, we requested a filibuster."

The LKP is playing hardball, demanding the cancellation of the electoral reform bill and the proposal to set up a new agency to investigate corruption involving high-ranking officials.

LKP chairman Hwang Kyo-ahn announced an end to his hunger strike Friday after being taken to hospital late Wednesday while fasting to protest the bills.

The ruling Democratic Party and three minor parties designated those bills as fast-track legislation in late April despite objections from the LKP.

The bill to adopt a new proportional representation system was automatically referred to a plenary session Wednesday.

National Assembly Speaker Moon Hee-sang earlier announced a plan to refer the bill on the probe unit to a plenary session on Dec. 3.

Under the parliamentary law, if one third of lawmakers request a filibuster over a bill referred to a plenary meeting, unlimited discussions are allowed.

The LKP move will likely stall the handling of the country's 2020 budget bill. A legal deadline for the passage of the budget proposal is Monday.

Public criticism will likely mount as the filibuster will affect a host of bills linked to people's lives, including a revision to the road traffic act to strengthen children's safety in school zones.

Hundreds of bills were scheduled to be put to a vote Friday, including a set of three bills designed to improve accounting transparency for private preschools.

DP lawmakers held a rally at parliament to condemn the LKP for taking "hostage" of bills linked to people's lives.

"Stalling the passage of such bills with a filibuster amounts to paralyzing parliament," DP chairman Lee Hae-chan said.

"For the sake of the people and the nation, we will push for the passage of the political and judiciary reform bills," he said.

Minor parties rebuked the LKP's delaying tactic as a "tyranny" of the largest opposition party.

Filibuster was abolished in 1973, then re-introduced in 2012 when the National Assembly law was revised. It was part of efforts to prevent ugly scenes of physical scuffles among lawmakers over bill passages.

In 2016, the then-main opposition Minjoo Party, predecessor of the DP, staged a record-long filibuster to block a government-backed anti-terrorism bill. The measure was immediately put to a vote when the party ended the filibuster. (Yonhap)