Human rights activists have compared detention facilities for refugees arrested by the Kenyan government to "concentration camps".
Prisoners go days without being fed and families are not allowed to visit without paying officials bribes, according to Almin Kimathi a local campaigner.
Around 3,000 refugees, mainly of Somali origin are being held for what authorities claim are security reasons. Kenya blames Somalia-based fighters for a number of attacks on its soil.
Al Jazeera's Haru Mutasa reports from Nairobi.