Many political watchers expected the opposition bloc to face an uphill battle ahead of the nationwide local elections in June, but few could have predicted that the solution would be another new party, especially one that combines the largest opposition party with the emerging party of a popular independent.

On Sunday, Kim Han-gil, the chief of the main opposition Democratic Party, and Ahn Cheol-soo, a former presidential candidate with his own party in the making, announced that they would join forces to create a coalition party to challenge the ruling camp in the June 4 local elections.

"The two sides will push for unification through the creation of a new party for new politics at the earliest possible date and achieve a transfer of power in (the presidential election in) 2017 based on this," Ahn said in a joint press conference with Kim at the National Assembly.

The June elections for mayors, governors, councilors and education superintendents are seen as a mid-term confidence vote for the Park Geun-hye government, which marked the first anniversary of its inauguration on Tuesday.

The DP hasn't won a single election in recent years, which puts the party in a desperate need to win back public confidence.

The political union foremostly changes what has been a three-way rivalry among the ruling Saenuri Party, DP and newest but strong camp commanded by Ahn. It also changes the assumed lineup of candidates for the local elections that include bellwether positions like the Seoul mayor and governors in strategically important regions.

Saenuri will have to go up against a strengthened opposition that now has Ahn in the mix. Ahn, a fledgling politician who has yet to prove himself on the big stage, still has a formidable following and may have enough of a force to tip the election in the opposition's favor.

Relations between the ruling and opposition parties have been badly frayed in Park's first year in office due to a series of scandals, including allegations that the state spy agency and other government bodies helped her win the 2012 presidential vote by manipulating public opinion through Internet posts.

More recently, the DP and Ahn were drawn closer together when the Saenuri Party decided to scrap its presidential campaign pledge to abolish the top-down nomination system for local election candidates.

The ruling party decided instead to implement a bottom-up nomination system that would give party members and the general public the right to pick candidates for mayors and councilors.

Scrapping the nomination system was a key campaign pledge of the ruling party, the DP and Ahn, who ran as an independent candidate in the 2012 presidential race before he dropped out to back the then DP candidate, Rep. Moon Jae-in.

The top-down system has long been associated with bribes between those wanting nomination and the party.

Amid the controversy, Ahn announced last week that his upcoming party would not nominate candidates for mayors and councilors, and urged the DP to do the same.

Before Ahn's announcement, the DP had appeared to be shifting toward keeping the nomination system out of concerns that the DP could lose the elections if it doesn't nominate candidates while the ruling party does.

But doing so would have invited public criticism that it, too, broke its campaign pledge.

"The government and the ruling party are not repenting or apologizing for their lies during the presidential election, filled with arrogance and self-righteousness and deceiving the public again ahead of the local elections," Kim said during the news conference. "(We) have decided not to nominate candidates (for mayors and councilors) in the local elections as promised to the people."

The ruling party immediately denounced the coalition as "collusion" between an emerging party incapable of self-rehabilitation and a No. 1 opposition party desperate to pair up.

"Does mixing 50 degree water (with 50 degree water) make it 100 degrees?" ruling party spokesman Park Dae-chul asked in a press briefing at the party's headquarters. "It's totally illogical and self-contradictory."

He especially criticized the DP for "abandoning its values and pride" in another attempt to form an election alliance.

"I can't even count the number of times the Democratic Party has created a (new) party," Park said.

The spokesman also accused the DP of bowing to pressure from Ahn to abandon the nomination system, despite indicating earlier that it would keep it.

"The DP tried to deceive the public," he said. "The Saenuri Party will remain unshaken and calm at the opposition's pairing, keep our eyes fixed on the people and strive for responsible politics for the people." (Yonhap)