South Korea's ruling Saenuri Party was overtaken by a minor opposition party in approval ranking for the first time after its public support fell for the eighth consecutive week amid the on-going scandal involving President Park Geun-hye and her confidante, a poll showed Thursday.

According to the pollster Realmeter, its approval rating came to 16.7 percent this week, down 2.3 percentage points from a week earlier.

It hovered below the People's Party, which garnered 17.9 percent, becoming the third player in terms of public approval. The main opposition Democratic Party posted 33.4 percent, up 2.9 percentage points.

The ruling party has been dogged by an internal feud among Park-loyalists and their opponents, sparked by the scandal surrounding Choi Soon-sil, who allegedly exerted power over state affairs and enjoyed various illegal benefits.

On Wednesday, Rep. Kim Moo-sung, former head of Saenuri, announced he will push for Park's impeachment, which is widely seen as a catalyst to rally party members behind the suprapartisan campaign to unseat the president. Three opposition parties joined forces to seek a parliamentary impeachment of Park.

Earlier this week, Gyeonggi Gov. Nam Kyung-pil and third-term lawmaker Kim Yong-tae announced their decision to leave Saenuri.

Moon Jae-in, former head of the main opposition, stood as the most favored presidential contender for next year's race with 21.2 percent approval, up 0.8 percentage point from last week. UN Secretary-General Ban Ki-moon followed with 17.4 percent, down 0.7 percent.

The survey was conducted this week on 1,519 South Koreans, with a margin of error of plus or minus 2.5 percentage points. (Yonhap)