Rival camps battled on Wednesday to take the lead in the last public polls for the Oct. 26 Seoul mayoral by-election.

According to the election law, public survey results may not be made public during the last six days of campaigning, which is next Wednesday.

Also, the increasing number of swing votes made it impossible to predict the final results.

Among the three public polls published Tuesday and Wednesday, two were in favor of Grand National Party candidate Na Kyung-won but the gap between her and independent candidate Park Won-soon was within the margin of error.

Park, who had been leading in the polls until recently, has considered asking Ahn Chul-soo to back his campaign, further boosting expectations that the entrepreneur-turned-professor may once again step onto the political playing field.

“Prof. Ahn, though he denied having political plans, made it clear that he is against the GNP,” said Park in a radio program on Wednesday.

“I shall consider reaching out for his help.”

Both camps also worked to attract the increasing number of swing voters.

According to the joint survey conducted by the local broadcasters, the number of swing voters rose up to 21 percent, a visible rise from the maximum 10 percent predicted in the early stage of the race.

Observers speculated that a large part of the voters were disillusioned by the mudslinging game between the parties and between candidates and withdrew their active support.

Parties nevertheless stepped up their morality accusations against the other’s candidate.

The GNP kept raising suspicions of military evasion and academic forgery by Park, which have greatly hurt the activist’s support rate so far.

“People cannot but doubt Park, who refused Na’s suggestion to hold an in-depth open forum,” said GNP floor leader Rep. Hwang Woo-yea.

“Democracy is based on thorough examination and debates, and Park should be ready for such processes, if he plans on challenging for the mayoral post.”

The DP, on the other hand, tackled Na’s suspected real estate speculation and also slammed the GNP and the Lee Myung-bak administration over the president’s retirement home.

Amid the heated fight, presidential potentials also stepped up their campaigns.

Former GNP chairwoman Rep. Park Geun-hye and DP chairman Rep. Sohn Hak-kyu both visited Inje, Gangwon Province, on Wednesday.

As the province is heavily dependent on agriculture and fishing, the Korea-U.S. Free Trade came up as a key issue for both figures.

Park, during her visit to a fishing corporation, listened to the fishers’ complaints and proposals over the trade agreement.

Sohn mostly underlined the irregularities of the deal and pledged to establish protective measures for local industries.

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