The death toll in the Tuesday evening accident along Keroka -Nyangusu road has hit 10 after three more people succumbed to their injuries hours later.
Seven people including two pedestrians were killed on spot after a Probox car veered off the road and landed in the ditch near Keroka town.
Those riding in the car had reportedly gone for a funeral ceremony in Riasena, miles away from the accident secne.
Area police boss Philip Wambugu said the car had failed breaks leading to the disaster, the second of its kind in as many weeks.
"The car failed breaks and it feared off the road. It also killed two pedestrians who happened to be at the scene," he said.
Reports from Kisii Teaching and Referral Hospitals indicate that three more people succumbed to their injuries on Tuesday night.