Oh Se-hoon of the main opposition People Power Party is on track to be named Seoul mayor in Wednesday's by-elections, with exit polls indicating a wide lead against his main rival.
  
According to the poll jointly commissioned by terrestrial broadcasters KBS, MBC and SBS, Oh had 59 percent of voter support versus 37-point-7 percent that backed Park Young-sun of the ruling Democratic Party.

The survey by pollsters Hankook Research, Korea Research International and Ipsos was conducted across 50 voting stations on around 10-thousand voters after they cast their ballots. It has a margin of error of plus-or-minus one-point-seven percentage points and a confidence level of 95 percent.

Oh had served as Seoul mayor from 2006 to 2011. His second term was cut short when he abruptly resigned after losing a referendum on free school lunches.

Turnout for early voting in the by-elections, conducted last Friday and Saturday, had reached 20-point-54 percent, a record high for any by-election.

The election results for the mayorships in Seoul and Busan are critical for both political parties as they are viewed as a bellwether for next year's presidential election.