The main opposition New Politics Alliance for Democracy took nine of the 17 metropolitan mayoral and gubernatorial races in Wednesday's local elections, as the ruling Saenuri Party fared better than expected taking eight.
Although the NPAD fared well, the main opposition is not home free, with mixed exit poll figures indicating that its strategy of using the local elections to "pass judgment" on the Park Geun-hye administration is likely to lose steam.
The elections were seen as a referendum for the administration in the wake of the April 16 ferry disaster that left more than 300 people dead or missing. The government has been sharply criticised for its poor handling of the accident.
Among the NPAD's victories, Park Won-soon took Seoul beating Saenuri Party's candidate Chung Mong-joon with a comfortable lead of over 12 percentage points to win his second term.
The NPAD also took the Chungcheong provinces, which traditionally have conservative tendencies, and succeeded in defending Gwangju against a former colleague, despite earlier worries.
The ruling party, which went into the local elections with a decreased ratings, won some of the more hotly contested areas.