The parliamentary ethics committee passed a motion in a unanimous decision Wednesday to expel a sitting lawmaker -- formerly affiliated with the ruling party -- accused of sexual assault.

Rep. Sim Hag-bong, who left the ruling Saenuri Party last month, is being investigated by prosecutors on suspicion of sexually assaulting a woman in her 40s at a hotel in Daegu on July 13.

The National Assembly's Ethics Committee took the disciplinary action against the embattled lawmaker and will send the motion to the National Assembly's general meeting for approval.

The motion is likely to be tabled on Oct. 13 as it needs at least a two-thirds approval to be passed. If the motion passes, it would be the first time for a sitting lawmaker to be ousted from the parliament for ethics reasons.

The committee's meeting comes after a group of 25 female lawmakers from the main opposition New Politics Alliance for Democracy filed a motion, calling for Sim to be punished.

Sim left the ruling party on Aug. 3, noting that he did not want to place any burden on it.

The Saenuri Party accepted Sim's letter of defection. His defection lowered the number of seats held by the ruling party in the 298-member parliament to 159. (Yonhap)