A co-chair of the main opposition United Future Party’s(UFP) general election committee warned the UFP may lose parliamentary seats, and drop under 100, the minimum required to block attempts to revise the Constitution.

At a meeting with reporters on Monday, Park Hyeong-jun said he felt a sense of crisis from conducting polls and analyzing the election situation over the weekend.

The warning comes after Cha Myung-jin, the UFP candidate for Gyeonggi Province's Bucheon-C district, claimed during a debate that bereaved family members of victims of the 2014 Sewol ferry sinking engaged in promiscuous acts with a volunteer in a tent at the memorial space.

Cha has continued making such claims during his campaign after the UFP took steps to recommend that he defect from the party.

The UFP leadership now plans to expel him later on Monday.

Referring to the ruling bloc's estimate of winning 180 seats, Park asked voters to support the UFP and its satellite Future Korea Party to prevent the ruling side from monopolizing parliament and threatening democracy.