The group says the prayer days are in contravention to students' rights.

Public schools have a tradition of organising for prayer days before students sit for national examinations.

Schools have this week called parents to join in the tradition to pray for a smooth examination period.

“Most Kenyans have gone through a public education system where organised, mandatory observance of religious practice was a must," the atheist association wrote in part.

The group says children should be left to make their own unbiased decisions about religion.