A bus carrying employees from a diamond mine in Limpopo reportedly collided with a lorry. Road safety is a critical challenge in South Africa, despite the country's advanced road infrastructure

At least 20 employees of mining giant De Beers have been killed in a road accident in South Africa, local officials said on Sunday.

Spokesperson for the Department of Transport and Community Safety in Limpopo Vongani Chauke told AFP news agency that the bus had been shuttling staff from the Venetia Diamond Mine, operated by De Beers, when it crashed in the north of the country.

“The bus came into collision with a lorry,” said Vongani Chauke.

Chauke told AFP the accident happened at around 1600 GMT, some 25 kilometres (15 miles) from the mine, at the village of Musian on the border with Zimbabwe.

Details surrounding the cause of the collision are not yet known.

The Venetia mine is the largest diamond mine in the country, accounting for more than 40 percent of South Africa's annual diamond production, and employing more than 4,300 people.

In July, De Beers announced the start of underground diamond production from the new seams opened underneath the open-cast mine.

The deadly accident comes months after a head-on collision between a bus and a cash-in-transit van claimed 20 lives in northern Limpopo province, leavingdozens injured.

After the crash the bus rolled from a bridge on the N1 freeway into a river below, said ER24, whose paramedics were on the scene.

"Three people were found deceased by the roadside and 16 down by the river - all were declared dead on arrival," ER24 had said in a statement.

"One patient, of the 69 passengers confirmed transported to hospital for various injuries, has since died," it had said.

South Africa ranks highly when it comes to road infrastructure on the continent, however it also has a questionable road safety record.

Each year thousands of people are killed on the country's roads.

South Africa's Road Traffic Management Corporation (RTMC) said in May that 12,436 people were killed on the country's roads between January 2022 and December of the same year.