The minor Minsaeng Party filed a constitutional appeal and injunction on Monday against the ruling and main opposition parties' respective satellite entities, claiming they were set up to take advantage of the mixed-member proportional representation system.

The move came a day after party chief Sohn Hak-kyu held a press conference announcing they would seek a ruling from the Constitutional Court on the constitutionality of the two satellite parties' registration approval process.

In an interview with a local radio program on Monday, Sohn accused both the Together Citizens' Party and Future Korea Party of violating a political party's duty to affirm constitutional order and play a role in the formation of public opinion.

Referring to the election atmosphere in the traditional liberal stronghold of the Jeolla provinces, Sohn said there is a growing sentiment to give proportional votes to the Minsaeng Party to prevent the ruling Democratic Party(DP) from becoming arrogant.

Sohn then asked voters to support his party, which is solely focused on improving people's livelihoods, when they head to the polls on April 15.