Kenyan opposition to the trials of President Uhuru Kenyatta and Deputy President William Ruto have gained traction since last month's deadly terror attack by militants on an upscale Nairobi shopping mall, which underscored the country's strategic importance in eastern Africa.
The ICC has charged Kenyatta and Ruto with crimes against humanity for their alleged roles in Kenya's 2007-08 postelection violence that killed more than 1,000 people. Both deny the charges.
Kamau said the council should also take into account the need to prevent "an aggravation" to peace and security in Kenya and neighbouring countries.
A delay would provide time for Kenya to consult the International Criminal Court "to consider how best to respond to the threat to international peace and security in the context of the Kenya situation," the ambassador said.
Kamau's letter was accompanied by a letter from the African Union's member states supporting a deferral for the Kenyan leaders.