The House of Commons deputy speaker Nigel Evans was rearrested on suspicion of indecent assault and sexual touching when he was answering bail on previous allegations.
It was the third time that Evans, 55, was arrested. He had gone to answer bail at a police station in Lancashire.
The Tory MP for Ribble Valley was originally arrested in May on suspicion of rape and sexual assault of two men. In June he was arrested on suspicion of three further offences of indecent assault, again involving men.
The latest offences are alleged to have taken place between 2002 and 2009 in London. They are said to involve two further victims.
Evans has denied all allegations. A friend said he would resign from his role of deputy speaker if he were charged with any offences.
"He continues to maintain that he is completely innocent but will resign as deputy speaker so that he can focus on his defence in open court," the friend said.
A Lancashire Constabulary spokesperson said: "A 55-year-old man from Pendleton in Lancashire has answered his bail following his arrest in May on suspicion of rape and sexual assault and in June on suspicion of three further offences of indecent assault.
"He has subsequently today been arrested on suspicion of Indecent assault and sexual touching of two further victims.
"He will be interviewed about these new allegations at a police station in Lancashire."
Swansea-born Evans has served as MP for Ribble Valley in Lancashire for more than two decades. He was elected in 1992.
He was appointed one of three deputy speakers of the House of Commons in 2010.