Temporary Sgt David Andrew Gibson, 43, is accused of misconduct in a public office. He has been suspended by Merseyside Police.
He is being investigated by the force's Anti-Corruption Unit, managed by the Independent Police Complaints Commission.
The officer is due before Liverpool City Magistrates on 18 June.
A police officer has been charged after allegations he engaged in a sexual act with a prostitute while he was on duty.