Transport Minister Dipuo Peters has urged local traffic authorities and the police to work together to get to the bottom of the cause of the accident on the R555 road in Mpumalanga, on Friday.
Preliminary reports indicate that a truck and minibus taxi collided head on resulting in the death of 15 people and a serious injury.
The case has been reported to the Witbank police.
The Road Traffic Management Corporation (RTMC) has since dispatched a team of crash and incident reconstruction and investigation experts to determine the cause of the crash.
"They must leave no stone unturned in getting to the bottom of the cause of this horrific crash," the minister said.
Peters has expressed sadness and shock following the untimely and unnecessary death of 15 people.
"We are indeed deeply saddened by this tragic occurrence. We send our deepest and sincere condolences to the families, the relatives and friends of those who lost their lives and we wish those injured a speedy recovery," Peters said.
The Road Accident Fund (RAF), an agency of the Department, will assist the families of the deceased and those injured with the necessary support during this period of grief.
Minister Peters has also called on motorists, passengers and all road users to be and remain vigilant at all times on the roads. She has called for a partnership with all of society in the fight against the carnage on South Africa's roads.
"Road safety is a responsibility of every single one of us. Let us put all hands on deck and bring a stop to this carnage. Together, we can save millions of lives," she said.