Plaid Cymru MP Jonathan Edwards has been arrested after a report of an incident.
The Carmarthen East and Dinefwr MP was arrested on May 20 at his home.
A spokesman for the party said that the whip had been withdrawn from Mr Edwards pending the conclusion of a police investigation.
He said: “On May 20th, Jonathan Edwards MP was arrested following a report of an incident.
“The party whip has been withdrawn pending the conclusion of a police investigation.
“Mr Edwards has accepted this course of action and is complying fully with the police enquiries.
“It would be inappropriate for the party to comment further at this time.”
Mr Edwards, 44, has represented Carmarthen East and Dinefwr since May 2010 when he replaced Plaid’s Adam Price.