A row is brewing between the US and South Africa after a veteran of the struggle against apartheid was refused a visa.

Tokyo Sexwale had intended to be in the US on Thursday to witness the first appearance of the South African mining firm Gold Fields, of which he is a director, on the New York Stock Exchange.

But in the end only his long-time comrade, former President Nelson Mandela, was in New York to ring the bell and open trading.

Mr Sexwale had been denied a visa because during the apartheid era he had been sent to prison by the South African government for throwing a grenade at police while smuggling weapons.

Anyone with a record of serious crime is permanently barred from getting a visa to the US without special dispensation.

The incident has incensed opinion in South Africa.

"We struggled under the banner of the ANC (African National Congress)," Mr Sexwale told reporters as he watched the ringing of the bell on satellite TV in the ANC's Johannesburg headquarters.

"It would be very unfortunate to find that we have to serve other sentences for fighting apartheid."

And the government was just as angry.

Calling the situation "incredible" and "amazing", foreign minister Nkosana Dlamini-Zuma said she had objected in writing and in person to the US ambassador to South Africa.

"We reject this with the contempt it deserves," she said.

She added that until 11 September, waivers were routinely granted to senior ANC members without the need to apply.

The US administration had assured her it would work to prevent a repetition, she said, but had warned that the necessary congressional action could take a long time.

US authorities were embarrassed by what appeared to be an administrative mistake rather than a deliberate slight.

Denying that the ANC was still seen as a terrorist organisation, a State Department spokesman said Mr Sexwale only applied for the visa 24 hours before he was due to arrive - too short a time to get the waiver approved by Washington DC.

"If it is determined that you have been convicted of a serious offence, you are declared permanently ineligible to receive a visa," said Judy Moon, a spokeswoman for the US Embassy in Pretoria.

"You may apply for a waiver of that, and that must be decided in Washington."

Technically that means that Mr Mandela - having served 27 years as a political prisoner - also needs a waiver.

Ms Moon refused to say whether he had applied for one, saying she could not comment on individual cases.