Next week's by-election has greater significance than others in years past, and the rival parties know it.
Fifteen parliamentary seats are up for grabs, the largest number in by-election history.
But political analysts say neither the ruling Saenuri Party nor the main opposition New Politics Alliance for Democracy have managed to wow voters with their campaigns.
"President Park Geun-hye's administration failed to win the support of the people as it struggled with appointing members for the new Cabinet and the main opposition party has shown political controversies when fielding candidates."
The main opposition leadership took heat this week for nominating former police officer Kwon Eun-hee to run for a seat in Gwangju's Gwangsan-B constituency.
She has been accused of a string of wrongdoings ranging from plagiarism to perjury.
"Right now, I think the fact that the opposition party is not doing so well a lot of it has to do with people becoming very concerned about Kwon Eun-hee and the legitimacy of her candidacy. I think that's going to play a big role for this election."
If the main opposition does not do as well as they hope, pundits expect that co-leader Ahn Cheol-soo will be held responsible and that his status may weaken within the party.
"With no clear winner expected in next week's by-elections rival parties are making their final pitches to win the hearts of voters.
Ji Myung-kil, Arirang News.