The National Assembly's Special Committee of Ethics passed a motion Wednesday to strip Rep. Sim Hag-bong of his title for an alleged sex assault.
The motion will be sent to a general meeting and if passed will be forwarded to the National Assembly's general meeting slated for next month.
The motion needs approval from at least two-thirds of lawmakers to get a final pass.
If passed, it will be the first case of a lawmaker expelled for an ethical lapse.
Expulsion is the most severe form of punishment for lawmakers under the National Assembly law.
The prosecution is investigating Sim for allegedly sexually assaulting a woman in her 40s at a hotel in the southeastern city of Daegu on July 13.
Sim left the Saenuri Party on Aug. 3, saying he did not want to “place a burden on the party.”