The violence has often degenerated into ethnic clashes over decades-old grudges about land and resources, with much of the anger aimed at Kibaki's Kikuyu tribe, who are resented for their domination of politics and the economy.
The latest fatalities occured along the Kisii-Kalenjin tribal border and in nearby areas of Nyamira district, a local police commander said.
"Fighting is going on along the border, people are fleeing homes," he said.
The latest deaths brought the total to about 70 dead since Friday in area where police have now launched a crackdown on ethnic fighting.
Men armed with clubs, sharpened sticks and machetes patrolled roads in the Rift Valley on Sunday, while scores of people fled ethnic attacks on their homes in heavily armed police convoys.
A Reuters news agency said that he saw police fire shots to disperse a gang manning a roadblock, allowing a busload of refugees to flee to safety.
"We're just keeping the peace around here," Charles Cheriot, who was manning at a roadblock where youths sharpened machetes on rocks and lined up arrows they said were poisoned, said.
"The police have taken sides. We just patrol."
At a hospital in the town of Kisii staff said that injured people were streaming in after being attacked with bows and arrows.
"We had one patient with an arrow in the neck from clashes overnight, so that's been 18 so far," Dr Wycliffe Mogoa, Kisii hospital medical superintendent, said.
"It has been bad. All these arrow wounds - you have to open up the wounds then remove the arrows. But we've managed."Peace plan
Despite the efforts of Kofi Annan, the former UN secretary-general, Kibaki and Odinga remain opposed.
A deal marking out a joint roadmap to end, within two weeks, the violence was agreed last week but it was unclear how the political issues would be addressed.
The agreement calls for illegal militias to be disbanded and for investigation of all crimes connected to the violence, including those allegedly committed by the police, who have killed scores of people.
The document was negotiated came only hours after Kibaki made an uncompromising speech at an AU summit in Addis Ababa, the Ethiopian capital, in which he insisted that opposition protests over the election results be taken to court.
He accused the Orange Democratic Movement (ODM), led by Odinga, of instigating the violence.
Odinga rejected the claims and said Kibaki was undermining peace talks.