The ruling Saenuri Party is struggling to fend off a strong opposition challenge in Busan, one of its traditional strongholds in the southeastern region.

To drum up support for her party in next month’s parliamentary election, Saenuri chief Park Geun-hye travelled to the port city Tuesday, her third visit in a month’s time.

“New politics that Saenuri dreams to realize is starting right here in Busan,” Park said in front of party members gathered at its local office.

“I ask you to change our politics and change Busan,” she said.

The leader’s visit came as the party’s candidates suffered a series of setbacks recently in key races there.

“The situation down there looks pretty tough,” a Saenuri insider said.

In one of the most high-profile cases, Son Su-jo, the Saenuri candidate for the city’s Sasang constituency, came under fire after she withdrew a pledge to campaign with just one-fifth of the money legally allowed.

The 27-year-old political novice has been the party’s hidden card against Moon Jae-in, a rising political star of the liberal opposition Democratic United Party, who is testing his electoral clout by running for a parliamentary seat there.

A latest survey showed that Moon extended his lead over Son by nearly 20 percentage points. The JoongAng Ilbo poll found Moon with 53.4 percent against Son with 33.3 percent.

In another key showdown, Saenuri-backed former prosecutor Kim Do-eup is locked in a neck-and-neck race with DUP’s actor-turned-supreme member Moon Seung-keun.

Moon Dae-sung, an Olympic gold medalist in taekwondo and member of the International Olympic Committee, is contesting Saha-A constiutency on the party’s ticket, and was recently accused of plagiarizing his doctorate papers.

The Saenuri chief met Son in a show of her continuing support for her, despite the controversy.

“I see you’re going through difficulties, but you’re doing fine,” she said to Son in the unscheduled meeting.

On the opposition side, Han Myeong-sook, the DUP chairwoman, and her counterpart from the United Progressive Party plan to travel to the city Wednesday to launch a joint campaign headquarters. The DUP and UPP have joined forces to take a legislative majority from Saenuri.

On Tuesday, Han visited Gwangju, a liberal heartland in the southwestern region increasingly challenged by independents.

“I admit that the mood here is not as favorable to us as in past elections,” Han said, apologizing for mishaps in the selection of candidates for the region.

A score of DUP members defected from the party in protest against the party’s nomination process and are now running as independents in constituencies there.

“The DUP will reflect on all the disappointments. I ask you to support us once more,” she said.

By Lee Sun-young (milaya@heraldcorp.com)