The bodies of children were among the dead. Police said exhumations are ongoing.
The shallow graves are in Shakahola forest, where 15 members of the Good News International Church were rescued last week.
Church leader, Paul Makenzie Nthenge is in custody, pending a court appearance.
State broadcaster KBC described him as a “cult leader”, and reported that 58 graves have so far been identified.
One of the graves is believed to contain the bodies of five members of the same family – three children and their parents.
Mr Nthenge has denied wrongdoing, but has been refused bail. He insists that he shut down his church in 2019.
He allegedly told followers to starve themselves in order to “meet Jesus”.
Kenyan daily, The Standard, said pathologists will take DNA samples and conduct tests to determine whether the victims died of starvation.
Police arrested Mr Nthenge on 15 April after discovering the bodies of four people suspected of having starved themselves to death.
Victor Kaudo of the Malindi Social Justice Centre told Citizen TV “when we are in this forest and come to an area where we see a big and tall cross, we know that means more than five people are buried there”.
Kenyan interior minister, Kithure Kindiki, said all 800 acres of the forest had been sealed off and declared a crime scene.
Mr Nthenge allegedly named three villages Nazareth, Bethlehem and Judea and baptised followers in ponds before telling them to fast, The Standard reports.
Kenya is a religious country and there have been previous cases of people being lured into dangerous, unregulated churches or cults.
