The first white South Africans granted refugee status under a programme initiated by US President Donald Trump boarded a plane to leave from the country's main international airport in Johannesburg on Sunday.

A queue of white citizens with airport trolleys full of luggage, much of it wrapped in theft-proof cellophane, waited to have their passports stamped, a Reuters reporter saw, before they entered the departure lounge for their charter flight.

"One of the conditions of the permit was to ensure that they were vetted in case one of them has a criminal issue pending," South African transport department spokesperson Collen Msibi told Reuters, adding that 49 passengers had been cleared.

Journalists were not granted access to those headed to the US.

Msibi said they were due to fly to Dulles Airport just outside Washington, DC, and then on to Texas.

Trump's offer of asylum to white South Africans, especially Afrikaners - the group with the longest history among white settlers in South Africa and who make up the bulk of whites - has been divisive in both countries.

In the United States, it comes as the Trump administration has blocked mostly non-white refugee admissions from the rest of the world. In South Africa, it coincides with heightened racial tensions over land and jobs that have dogged domestic politics since the end of white minority rule.

Despite a wider freeze on refugees, Trump called on the US to prioritise resettling Afrikaners, descendants of mostly Dutch early settlers, saying they were "victims of unjust racial discrimination."

The granting of refugee status to white South Africans - who have remained by far the most privileged race since apartheid ended 30 years ago - has been met with a mixture of alarm and ridicule by South African authorities, who say the Trump administration has waded into a domestic political issue it does not understand.

Three decades since Nelson Mandela ushered democracy into South Africa, the white minority that ruled it has managed to retain most of the wealth that was amassed under colonialism and apartheid.

Whites still own three quarters of private land and about 20 times the wealth of the Black majority, according to the Review of Political Economy, an international academic journal. Whites are also the race least affected by joblessness.

Yet the claim that minority white South Africans face discrimination from the Black majority has been repeated so often in online chatrooms that is has become orthodoxy for the far right, and has been echoed by Trump's white South African-born ally Elon Musk.