The matatu was heading to Mwatate from Voi when it hit the other vehicle, said Taita Taveta police commander Fred Ochieng.
It was ferrying mourners to Ngulu area in Werugha when the accident took place at Landi area.
They were transporting the body of a woman who died in Mombasa.
Eight people were injured in the accident.
Elisha Wawaka, a relative who helped rescue victims, said said all the five people died at the scene.
Speaking to The Star on phone, he identified four of them as the deceased's brother-in-law, her father-in-law and two grandchildren.
“The injured were taken to Moi referral hospital in Voi and later transferred to Ikanga private hospital due to the ongoing nurses' strike," he said.
Wawaka said the fifth person died at the private facility on Friday morning while another is in critical condition.
The police commander said the matatu driver got off his lane and lost control after hitting the canter. The vehicle overturned.
Ochieng said the bodies were taken to the Moi hospital morgue.
He said investigations were launched to establish the cause of the accident.
“Motorists should be cautious on unmarked roads. They should avoid speeding at night due to poor visibility,” he said.
-The Star| RAPHAEL MWADIME