The five-judge bench said it had no jurisdiction to hear matters on qualification or disqualification of presidential candidates, The Daily Nation of Kenya reported.
Kenyatta, the deputy prime minister, and former MP Ruto face charges of crimes against humanity at the International Criminal Court in the Hague.
The two are accused of masterminding violence that followed a disputed presidential election in 2007.
Kenyatta, Ruto and two other defendants have asked the International Criminal Court to push back their April trials because of delayed witness disclosures, The Star of Kenya reported.
The defendants want the trials to start four months after the final witness disclosure.