The international relations and co-operation department was on Sunday following up on reports that a South African man had been arrested in Sudan.
“We've noted the reports and are following up through our mission in Sudan,” spokesman Clayson Monyela said.
The South African was part of a group of four men captured by the Sudanese military in the tense Heglig oil region, French news agency AFP reported. The other three are a Briton, a Norwegian and a South Sudanese man.
“We captured them inside Sudan's borders, in the Heglig area, and they were collecting war debris for investigation,” Sudanese army spokesman Sawarmi Khaled Saad told AFP after the four were brought to Khartoum.
A colleague of one of the men said they were deminers working on the South Sudanese side of the border.
The British embassy was “urgently” investigating the arrest of its citizen and had requested consular access, AFP reported.
Jan Ledang, country director for the Norwegian People's Aid mission in South Sudan, identified one of the captives as employee John Sorbo.
“It's impossible that they were in Heglig. They were in Pariang about a 90-minute drive from Heglig in the South's Unity state,” Ledang told the agency.
The four were on a de-mining mission “and one of them was from the UN”, Josephine Guerrero, a spokeswoman for the United Nations Mission in South Sudan was quoted as saying.
“We're uncertain of the circumstances,” she added.
Heglig, Sudan's main oil region, has been at the centre of recent fighting between Sudan and South Sudan. - Sapa