A minor opposition party said Thursday its leader won't drop her candidacy for the upcoming general elections despite revelations her aides attempted to tamper with a crucial voter survey held to select a unified candidate among opposition hopefuls in a Seoul district.

Rep. Lee Jung-hee of the United Progressive Party was determined as a single opposition candidate in Seoul's Gwanak district following her victory in the telephone survey held this past weekend. But she has been under pressure to step down after two of her aides were found to have attempted to rig the survey.

The survey was held as part of the party's alliance agreement with the main opposition Democratic United Party to field a unified candidate in the April 11 parliamentary elections in order to avoid splitting opposition votes.

Lee, a lawyer-turned-lawmaker who has built an image as a "clean" politician, immediately apologized over the revelations but has refused to give up the candidacy, claiming she had no knowledge of the rigging and putting all blame on the aides.

She has demanded that a new survey be held to determine a candidate.

"There is no change in our existing position," a party official said Thursday, reaffirming that Lee won't give up the candidacy.

"There is no additional discussions or decision made about" her stepping down as a candidate, the official said.

The two campaign aides were found to have sent mobile phone text messages asking party members to lie about their ages if they get automated survey calls made randomly on Saturday and Sunday to ask voters in the constituency which hopeful they favor.

The survey was designed to select the winner by putting together responses from different age groups of voters, and the Lee aides attempted to boost her ratings among younger age groups, apparently on tips that enough responses from higher-aged groups had already been collected. (Yonhap News)