The Directorate of Criminal Investigations (DCI) on Monday evening arrested four Kenyans on Thika Superhighway on suspicion of transporting 22 victims of human trafficking.
The victims are all Eritreans and were being ferried in three motor vehicles.
Police sprung into action after being tipped off.
The suspects, Muhsan Shariff Abdikadir, Amin Shariff Abdul Qadir, Elias Mahabub and Muhamed Doyo are in police custody.
They are suspected of trafficking the victims aged between 15 and 38 years, with 17 of them being females.
The latest rescue comes just days after 23 Kenyans - who are suspected to be victims of human trafficking - were rescued from a house in Drumville Estate, Kamulu.
Those rescued included 22 women, aged between 21 years and 40 years, and a 38-year-old male.
Police revealed that the victims were being held awaiting trafficking to Saudi Arabia.