With just 30 days to go before voters cast their ballots, rival parties are entering into full-fledged campaign mode by completing their lists of candidates for a tough battle.

The April 13 poll is considered a crucial bellwether that could largely shape the local political landscape ahead of the presidential vote next year 

The ruling Saenuri Party, which has been split between those who are loyal to President Park Geun-hye and their opponents over how to select candidates for the election, sped up the nomination process.

Last week, Yoon Sang-hyun, a key member of the pro- Park faction and a former special political adviser to Park, was found to have used abusive language against party chief Kim Moo-sung, saying that Kim should not get a party ticket.

Kim has pushed ahead with reforming the party since resuming the chairman post in 2013, such as proposing a nomination system designed to allow ordinary people to select candidates for the parliamentary elections, while scores of lawmakers, including Yoon, opposed Kim's plan. 

In addition, internal polling data, including the names and approval ratings of the nominees, were leaked online, in violation of local election rules.

Despite a series of mishaps related to candidate selection, the rival members of a nomination committee vowed to make efforts to work out their differences over who will be picked to run in the election.

Chairman Kim has vowed that he will win 180 of the total 300 seats up for grabs in the general elections to scrap the controversial National Assembly Advancement Law.

Currently, the Saenuri Party controls 157 seats in the 293-member National Assembly, compared to 107 seats held by the main opposition Minjoo Party. Ahn's People's Party controls only 19 seats, one seat shy of forming a parliamentary negotiation bloc.

The bill grants lawmakers the right to challenge executive enactments, such as the government's enforcement ordinance, and allows more assembly power in reviewing and modifying government legislation.

The latest polls show that it will be difficult for the Saenuri Party to obtain 180 seats but it will keep its majority in the unicameral parliament.

"The Saenuri Party was earlier expected to grab more than 180 seats but everything changed due to an internal feud over the nomination process," said Kim Choon-seok of Hankook Research.

The main opposition Minjoo Party of Korea, meanwhile, is trying to reform itself by excluding scores of incumbent lawmakers deemed incompetent from being nominated for candidacy.

The opposition party unveiled a list of applicants who had been screened in its so-called cutoff. The list includes high-profile lawmakers.

The minor opposition People's Party, however, is still mired in an internal feud over a possible merger with the main opposition Minjoo Party ahead of the elections.

Rep. Kim Han-gil, the head of the party's election planning committee, resigned from his post after he failed to persuade the party's co-chairman Ahn Cheol-soo to join forces with the Minjoo Party to win more seats in the upcoming polls.

"The rival parties are still only interested in nominations when the general election is just 30 days away," said Lee Nae-young, a professor at Korea University, urging the parties to focus more on policy and issues related to the sluggish economy.

Three potential presidential hopefuls-- Kim Moo-sung, Moon Jae-in of the Minjoo Party and Ahn -- are heating up the campaign to prove their appeal to voters.

By law, Park is barred from seeking reelection after her single five-year term ends in early 2018.

A poll released Friday showed 16 percent of people supported Moon in a potential presidential race, followed by Kim who received 11 percent of support. Ahn is trailing behind, receiving 10 percent of support in the poll. 

Political analysts forecast that Kim will mostly likely be nominated for his electorate but he still has a lot to prove to his party members due to the ongoing feud between the factions.

Moon, who stepped down his chairman post earlier this year due to the strife, has not announced yet he will run for the election.

Some political analysts believe that he may run for electorates usually favorable to the ruling party since a victory in the tough district may possibly put him on a direct path to declare his candidacy for president. 

Ahn, who has many supporters in the 20-40 age brackets, also has to focus on winning in his electoral district of Nowon in northern Seoul, where he will be running against Lee Jun-seok, a 31-year-old entrepreneur from the Saenuri Party.

As presidential hopefuls prepare to drum up support in the run-up to the crucial political test, some districts have been highlighted as a battle for a bigger showdown. 

Oh Se-hoon, who stepped down from Seoul mayor in 2011, faces off against former veteran lawmaker Park Jin in the Jongno district in central Seoul. 

Another big match is expected in the Suseong district in the central city of Daegu, where former Gyeonggi Gov. Kim Moon-su, also considered a potential presidential contender from the conservative bloc, is campaigning against former lawmaker Kim Boo-kyum. (Yonhap)