Twelve people, including three children, were killed when a taxi overturned on the N1 highway near Touwsriver in the Hex River Valley on Saturday, said Western Cape Traffic Chief Kenny Africa.
"Early this morning, shortly after 03:00, a driver of a taxi lost control of the taxi and the vehicle overturned," Africa said in a statement.
"In this crash 12 people lost their lives: six male occupants, three female occupants, two boys and one girl died in this gruesome taxi crash just outside Touws River.”
Ten others were injured.
The vehicle was travelling towards Cape Town at the time of the crash.
The ANC said it was shocked and appalled by the latest road fatalities in the Western Cape and would earnestly like to appeal to all road users to respect and follow the rules of the road.
In a statement, Western Cape ANC provincial secretary Faiez Jacobs also appealed to road users to be more vigilant, tolerant and polite to one another.
Jacobs was referring to this latest incident.
"This is a most appalling start to the festive season and we are saddened by these road deaths. We would like to appeal to all road users to prioritise their own safety as well as that of others," Jacobs said in a Festive Season message.
Jacobs also appealed to road authorities to show zero tolerance to those who were deliberately violating road rules. "We cannot have mayhem ruling on our roads."
Wishing Western Cape residents and visitors to the province well over the Festive Season, Jacobs also urged them to be careful, safe, responsible and filled with reconciliation. He also expressed appreciation and thanks to those emergency services workers who would be on duty over this period.