The approval ratings of top presidential contender Park Geun-hye slipped more than two percentage points as her conservative ruling party took a beating over allegations one of its lawmakers bribed her way into parliament, polls showed Friday.

Park's rating stood at 36.4 percent in a survey of 1,500 people on Wednesday and Thursday, down from 39 percent during the same period last week, according to polling agency Realmeter.

A similar survey by Gallup Korea showed an approval rating of 35 percent for Park between Wednesday and Friday last week, down from 37 percent in the previous week's poll.

Allegations of the money-for-nomination deal were made public on Thursday last week, dealing a blow to the ruling Saenuri Party and its leading presidential hopeful ahead of December's presidential election.

The scandal centers on suspicions that Rep. Hyun Young-hee secured a proportional representative seat in April's general elections after paying 300 million won (US$266,150) to Hyun Ki-hwan, then a member of the party's candidate nomination committee. Park was chief of the party when the alleged money exchange took place in March.

"It appears that (Park's) approval ratings have dropped slightly due to the money-for-nomination scandal," said Lee Taek-soo, the director of Realmeter.

Park's apparently damaged reputation was also reflected in a two-way race with Ahn Cheol-soo, a software entrepreneur-turned-professor widely regarded as a serious challenger to Park should he run for president.

 On Wednesday and Thursday, Park's rating stood at 44.7 percent against Ahn's 48 percent in a reversal from Thursday and Friday of last week when she received 48.2 percent against Ahn's 44.8 percent, according to Realmeter.

The scandal has had such an impact on the ruling party that on Monday it decided to oust both Hyuns. The former nomination committee member is currently a deputy head of the party's think tank Youido Institute.

Despite a shared last name, the lawmaker and the former nomination committee member are not related.

Their expulsions are pending approval and are expected to be handled at a meeting of the party's Supreme Council early next week, Rep. Suh Byung-soo, the party's secretary general, told reporters.

Rep. Hyun's expulsion is subject to approval by at least two-thirds of the party's 149 lawmakers at a general meeting, while the fate of the former nomination committee member can be decided by the Supreme Council.

The general meeting could be held on either Monday or Tuesday, Suh said.

If expelled, the two Hyuns will be banned from returning to the party for the next five years. Rep. Hyun will, however, be able to keep her legislative seat as an independent. (Yonhap News)