The minority Unified Progressive Party is on the verge of losing its key support base as labor unions and grassroots groups distance themselves from their scandal-ridden political representatives.

The central committee of the Korean Federation of Trade Unions, a major umbrella group of trade unions, held an emergency meeting Friday to discuss its ties with the left-wing party amid its simmering feud over voting irregularities.

A majority of the labor group threatened to retract its support unless the embattled party resolves the messy dispute and conducts drastic reforms.

The KFTU is the UPP’s largest political and financial backer. The now defunct Democratic Labor Party, which the UPP is derived from, was founded by the KFTU as its bridgehead for entering institutional politics.

Soon after the party’s vote-rigging scandal rose to the surface, two KFTU members stepped down from the party’s steering committee.

The ties between the party and the KFTU have been sour recently as representatives of the union group failed to make it to the list of the party’s candidates for the April parliamentary elections. Union activists were also uneasy over the UPP mainstreamers’ allegedly pro-North Korean stance.

The party’s mainstreamers and their official leader Lee Jung-hee belong to the far-left National Liberation group.

KFTU-affiliated bodies also publicly criticized the divided party.

“The UPP should sincerely apologize to the people and prove its determination for reforms,” its metal workers’ arm said in a statement Thursday.

A public transport workers’ union pledged to take “extreme measures,” should the party refuse to change drastically.

The National Council of Center to Victims of Forced Evictions, another pillar supporter for the party, has already declared it will sever ties with the UPP.

“We feel betrayed by the UPP, which neglected its role as the people’s voice,” the council said in a statement.

The UPP held a steering committee meeting on Thursday but failed to reach a compromise as Lee once again denounced the fact-finding panel’s report and the other three co-chairs urged her to acknowledge the irregularity and to accept the consequences.

Kang Ki-kab, former DLP leader and the UPP’s emergency council chief, Friday suggested a two-way vote -- by party members and citizens -- to determine whether the disputed proportional representatives should resign as demanded by minority groups.

Both camps rejected the proposal instantly.

“Kang’s proposed voting method is a serious violation of party democracy,” said Lee Sang-kyu, lawmaker-elect and aide to Lee.

The escalating strife caused concern with the main opposition Democratic United Party, which allied with the UPP to compete against the majority ruling Saenuri Party in the parliamentary elections.

The DUP’s floor leader and interim chief Rep. Park Jie-won refrained from speaking out on the issue. He said that the scandal is not likely to subside very soon.

The progressive party took bombardment of criticism from conservative dailies. News outlets revealed the past pro-North Korean activities of its key figures, further weakening the public’s trust in the party.

By Bae Hyun-jung (tellme@heraldcorp.com)