Embakasi East Member of Parliament Babu Owino was reportedly arrested by flying squad officers outside Parliament buildings on Friday.
The Orange Democratic Movement (ODM) MP said he is being detained at Parklands Police Station.
Police are said to have questioned him over a recent incident in Westlands, where he and his bodyguards allegedly assaulted a Nairobi county parking attendant.
"They want to damage my image because they see me as a threat to becoming the Nairobi Governor in 2022," he told a local media via phone.
Earlier in the week, a video clip emerged showing him and his bodyguards roughing up a parking attendant at Fortis Plaza in Westlands, although he denied having being involved in such an incident.
In a Facebook post, Babu said: "Been arrested. Held at Parklands. Charges are two. Harbouring intention to overthrow government. Assault. It shall be well."