Public sentiment for the main opposition candidates in the April 7 mayoral by-elections for Seoul and Busan was found to be broadly outpacing their ruling party rivals in the final polls legally allowed before election day.

A joint survey of one-thousand-seven Seoul residents commissioned by KBS, MBC and SBS and conducted on Wednesday found 50-point-five percent said they planned to vote for the main opposition People Power Party’s(PPP) Seoul candidate Oh Se-hoon.

The ruling Democratic Party’s(DP) Park Young-sun had 28-point-two percent of the support.

The difference of 22-point-three percentage points was widely outside the poll's margin of error of plus or minus three-point-one percentage points, with a confidence level of 95 percent.

Oh had more support than his opponent across all age groups, with the exception of those in their 40s. Among moderates, 57-point-one percent supported Oh, while 22 percent supported Park. 

In the Busan mayoral race, support for the PPP's Park Hyung-joon came in some 20 percentage points higher than his DP rival Kim Young-choon, at 46-point-eight percent to 26-point-seven percent.

Starting Thursday through election day, the release of new opinion poll results concerning the by-elections is prohibited under the election law.