Paramedics have urged motorists to make sure their children buckle up, after a nine-year-old girl was killed and a four-year-old boy seriously injured in crashes at the weekend.
Netcare 911 spokesperson Chris Botha said there had been an increase in the number of preventable deaths of children in crashes.
"When a car is involved in a crash and a child is not buckled up, the little body keeps on travelling at the speed the vehicle was moving. The impact on their bodies is immense and they suffer severe trauma."
In one accident in Durban on Saturday, the driver of a BMW with four occupants lost control and smashed through the freeway's metal barriers.
Paramedics found a seriously injured four-year-old boy lying in the long grass.
"The child had been thrown from the vehicle, because he was not properly buckled up," Botha said.
"Paramedics deal with a lot of crashes and often have to witness the tragedy of children dying in vehicle accidents because they were not wearing seat belts."
On Friday night a nine-year-old girl, whose name has not been released, was killed on Nandi Drive in Durban.
Botha said both her parents had been wearing their seat belts and survived.
"It is tragic; she was not buckled up and died in the crash. We plead with parents to ensure children always wear seat belts while in a vehicle," Botha said.
He said motorists should be extra vigilant. "We are inundated with emergency calls and it's going to get worse once the inland schools close.
Children travel unsecured in taxis and other vehicles on their way to the beach and often what was supposed to be a fun day ends in tragedy," Botha said.
South Africa has one of the highest road death tolls in the world.
There are 26 child deaths for every 100 000 in crashes, compared with 1,7 for every 100 000 in the UK.
Between April 1 last year and March 31 this year, 538 child passengers under the age of 19 died in vehicle crashes, according to the Arrive Alive Traffic Report.