South Africa has criticised the United States following reports that Washington could received the first white Afrikaners it had offered to resettle as refugees as early as next week.

US media has reported that US President Donald Trump's administration plans to welcome the first group of white South Africans as early as Monday, after Trump accused Pretoria of "racial discrimination" against them.

In a statement published Friday, South Africa's foreign ministry contested the allegations and said the move was politically motivated.

"It is most regrettable that it appears that the resettlement of South Africans to the United States under the guise of being 'refugees' is entirely politically motivated and designed to question South Africa's constitutional democracy," the foreign ministry said.

"We reiterate that allegations of discrimination are unfounded," it said. "Moreover, even if there are allegations of discrimination, it is our view that these do not meet the threshold of persecution required under domestic and international refugee law."

South African deputy foreign minister Alvin Botes has raised the concerns directly with his US counterpart Christopher Landau, it said.

While challenging the US assessments of alleged refugee status, South Africa said it would "not block citizens who seek to depart the country from doing so".

Trump halted refugee arrivals immediately after taking office in January.

But in an executive order in February, he described Afrikaners as victims of "racial discrimination", opening the way for them to resettle in the US.

Reports said afterwards that thousands of Afrikaners had approached the US embassy in Pretoria about the resttlement offer.

US investigative outlet The Lever quoted a government source saying Washington was preparing to resettle up to 1,000 Afrikaners this year.

National Public Radio (NPR) said a group of 54 Afrikaans South Africans was scheduled to arrive Monday, citing three sources with knowledge of the matter.

The sources said a press conference was planned for the group's arrival at Dulles airport in Virginia, attended by high level officials from the Departments of State and Homeland Security.

Relations between South Africa and the United States have nose-dived this year over a range of domestic and foreign policy issues, culminating in Washington's expulsion of Pretoria's ambassador in March.

The South African government passed a new land reform bill in January that Trump has claimed would allow the South African government to seize ethnic minority Afrikaners' agricultural property "without compensation".

But so far no land has been confiscated and the government says the "expropriation without compensation" clause would be used only in rare instances after efforts had been made to reach a fair agreement with the owner.