The minor left-wing Justice Party with six incumbent lawmakers has come out against a proposal floated earlier this week by three major parties, except the majority party, to simultaneously hold a referendum on a constitutional revision and the presidential polls on May 9.

Rep. Sim Sang-jung, the head of the Justice Party, said Thursday that the constitutional revision proposal by the Liberty Korea Party, People's Party and Bareun Party is "too radical and improvised" to be widely accepted by the public. 

Sim said the revision proposal was politically motivated, and that there is not enough time to prepare fully before the May 9 election.

"It is an coup-like proposal that does not take people's sovereignty into consideration," Sim said during an interview with PBC Radio.

"Faced with slim chances of winning the presidency, the three parties must be seeking a turnaround through the amendment," Sim said.

The Justice Party's objection has further dimmed the outlook for the proposal, as the majority Democratic Party already dismissed the move.

The debate over a constitutional revision has erupted, as politicians and critics claim the current single five-year term presidency has failed to embrace social and political changes since the last revision in 1987.

Supporters of the revision say that the revision should be focused on enhancing power sharing among the three branches of government, arguing that the concentration of power in the president may have given birth to the ongoing political scandal that led to Park Geun-hye's ouster from presidency.

"(The revision) should go through sufficient discussion and win the consent of the people," Sim said. "I cannot understand the idea of seeking the amendment in tandem with the presidential polls which will come in just about 50 days." (Yonhap)