The main opposition People Power Party(PPP) and minor People’s Party(PP) announced on Thursday that they failed to agree on fielding a single opposition candidate for the April 7 Seoul mayoral by-election.

This comes after the two sides met again after PP candidate Ahn Cheol-soo accepted PPP candidate Oh Se-hoon's proposal to combine surveys of one-thousand people on each candidate's competitiveness and adequacy.

Both party secretary generals said there simply isn't enough time for the surveys before the registration period ends on Friday.

After registering the candidacies separately, the two sides are expected to continue negotiations until March 28, after which ballots will begin to be printed.

Meanwhile, the ruling Democratic Party(DP)'s Park Young-sun became the ruling coalition's Seoul mayoral candidate after she defeated Open Democratic Party candidate Kim Jin-ai in a primary on Wednesday.