The only survivor of the crash was an eight-year-old child, who was receiving medical attention, according to authorities in the northern province of Limpopo.

They said the child was seriously injured.

The Limpopo provincial government said the bus veered off the Mmamatlakala bridge on Thursday and plunged 50 metres into a ravine before busting into flames.

Search operations were ongoing, the provincial government said, but many bodies were burned beyond recognition and still trapped inside the vehicle.

Authorities said they believe the bus was travelling from the neighbouring country of Botswana to the town of Moria, which hosts a popular Easter pilgrimage.

They said it appeared that the driver lost control and was one of the dead.

Transport Minister Sindisiwe Chikunga was in Limpopo province for a road safety campaign and changed plans to visit the crash scene, the national Department of Transport said.

She said there was an investigation underway into the cause of the crash and offered her condolences to the families of the victims.

The South African government often warns of the danger of road accidents during the Easter holidays, which is a particularly busy and dangerous time for road travel.

More than 200 people died in road crashes during the Easter weekend last year.

The Zionist Christian Church has its headquarters in Moria and its Easter pilgrimage attracts hundreds of thousands of people from across South Africa and neighbouring countries.

This year is the first time the Easter pilgrimage to Moria is set to go ahead since the COVID-19 pandemic.

Australian Associated Press