Liberal Democrat MP Mike Hancock has been questioned by police following allegations of improper behaviour towards a female constituent.
In a statement on his website, the Portsmouth South MP said he had gone voluntarily to a police station and "co-operated fully" with inquiries.
He declined to comment on the details of the case, but has previously denied any wrongdoing and insisted he only offered "help and support" to the 36-year-old woman.
Hampshire Police's involvement came as Parliamentary Standards Commissioner John Lyon was also reported to have received a complaint regarding the MP's behaviour.
Mr Hancock said: "I can confirm that I was questioned on Tuesday 12 October by officers of the Hampshire Police in relation to allegations made against me by one individual.
"I attended the police station voluntarily, co-operated fully and answered all questions that were asked. Normal processes now have to be followed by the police, which I entirely understand.
"In the circumstances, and in accordance with legal advice, it would be inappropriate for me to make any further comment on this subject as to do so could prejudice due process."
He appealed for his family's privacy to be expected and said he intended to "carry on normally" with his work as an MP and Portsmouth City councillor.
Conservatives on the city council have called for Mr Hancock to be suspended while the investigation is carried out.
