Thabo Siavhe was welcomed earlier with tears and the happy shouts of his family as he arrived at OR Tambo Airport.

He was one of four foreigners held in Sudan since last month.

"I am so happy to be back, I just want to be with my family now," an emotional Siavhe said as relatives hugged and kissed him.

Asked about his experience in Sudan, he said he was as scared as anyone would have been in the same situation.

"I was at the wrong place at the wrong time, but they treated me good."

His two children, Lucky, one, and Ndivhuwo, four, seemed confused by the commotion when their father arrived.

His younger brother Musiwa Makumunyi summed up the family's joy: "We are so happy to have him safely back; we were so worried."

On Tuesday afternoon, Siavhe left for Limpopo where his family had planned a traditional celebration, including a cleansing ceremony, said his uncle Brehme Nefale.

Siavhe and the other three foreigners -- from Britain, Norway and South Sudan -- were arrested on Sudan's disputed border area with South Sudan.

Their release was announced on Sunday.

Mediation talks in Khartoum, led by former South African president Thabo Mbeki, paved the way for their freedom.

At the time of their arrest, Khartoum accused the four of "suspicious activities" in the disputed area of Heglig.

The United Nations said the group, which also included a UN employee and two staff of the South African demining group Mechem, was working on a UN-backed demining (locating and disabling landmines) assessment 145 kilometres away.

South Sudan separated from the north in 2011, but serious disputes over oil exports and border demarcation remain.

Mbeki has been a key player in attempts to find lasting peace between the two countries.

The Mechem group was delighted at Siavhe's safe return.

"Both Siavhe and his family will be provided with psychological support, as well as other support," spokeswoman Sinah Phochana said.

About 30 Mechem workers were at the airport with flowers and banners to welcome him.